The surface of the earth is approximately 70.9% water and 29.1% land. The former portion is divided into large bodies termed oceans. The World Factbook recognizes and describes five oceans, which are in decreasing order of size: the Pacific Ocean, Atlantic Ocean, Indian Ocean, Southern Ocean, and Arctic Ocean. Because of their immense size, the Pacific and Atlantic Oceans are generally divided at the equator into the North and South Pacific Oceans and the North and South Atlantic Oceans, thus creating seven major water bodies - the so-called "Seven Seas."

Some 97.5% of the earth's water is saltwater. Of the 2.5% that is fresh, about two-thirds is frozen mostly locked up in the Antarctic ice sheets and mountain glaciers worldwide. If all the surface ice on earth fully melted, the sea level would rise about 70 m.

Earth's land portion is generally divided into several, large, discrete landmasses termed continents. Depending on the convention used, the number of continents can vary from five to seven. The most common classification recognizes seven, which are (from largest to smallest): Asia, Africa, North America, South America, Antarctica, Europe, and Australia. Asia and Europe are sometimes lumped together into a Eurasian continent resulting in six continents. Alternatively, North and South America are sometimes grouped as simply the Americas, resulting in a continent total of six (or five, if the Eurasia designation is used).

North America is commonly understood to include the island of Greenland, the isles of the Caribbean, and to extend south all the way to the Isthmus of Panama. The easternmost extent of Europe is generally defined as being the Ural Mountains and the Ural River; on the southeast the Caspian Sea; and on the south the Caucasus Mountains, the Black Sea, and the Mediterranean. Portions of five countries - Azerbaijan, Georgia, Kazakhstan, Russia, and Turkey - fall within both Europe and Asia, but in every instance the larger section is in Asia. These countries are considered part of both continents. Armenia and Cyprus, which lie completely in Western Asia, are geopolitically European countries.

Asia usually incorporates all the islands of the Philippines, Malaysia, and Indonesia. The islands of the Pacific are often lumped with Australia into a "land mass" termed Oceania or Australasia. Africa's northeast extremity is frequently delimited at the Isthmus of Suez, but for geopolitical purposes, the Egyptian Sinai Peninsula is often included as part of Africa.

Although the above groupings are the most common, different continental dispositions are recognized or taught in certain parts of the world, with some arrangements more heavily based on cultural spheres rather than physical geographic considerations.

Based on the seven-continent model, and grouping islands with adjacent continents, Africa has the most countries with 54. Europe contains 49 countries and Asia 48, but these two continents share five countries: Azerbaijan, Georgia, Kazakhstan, Russia, and Turkey. North America consists of 23 sovereign states, Oceania has 14, and South America 12.

countries by continent: Africa (54): Algeria, Angola, Benin, Botswana, Burkina Faso, Burundi, Cabo Verde, Cameroon, Central African Republic, Chad, Comoros, Democratic Republic of the Congo, Republic of the Congo, Cote d'Ivoire, Djibouti, Egypt, Equatorial Guinea, Eritrea, Eswatini, Ethiopia, Gabon, The Gambia, Ghana, Guinea, Guinea-Bissau, Kenya, Lesotho, Liberia, Libya, Madagascar, Malawi, Mali, Mauritania, Mauritius, Morocco, Mozambique, Namibia, Niger, Nigeria, Rwanda, Sao Tome and Principe, Senegal, Seychelles, Sierra Leone, Somalia, South Africa, South Sudan, Sudan, Tanzania, Togo, Tunisia, Uganda, Zambia, Zimbabwe;

Europe (49): Albania, Andorra, Austria, Azerbaijan*, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Georgia*, Germany, Greece, Holy See (Vatican City), Hungary, Iceland, Ireland, Italy, Kazakhstan*, Kosovo, Latvia, Liechtenstein, Lithuania, Luxembourg, Macedonia, Malta, Moldova, Monaco, Montenegro, Netherlands, Norway, Poland, Portugal, Romania, Russia*, San Marino, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey*, Ukraine, United Kingdom (* indicates part of the country is also in Asia);

Asia (48): Afghanistan, Armenia, Azerbaijan*, Bahrain, Bangladesh, Bhutan, Brunei, Burma, Cambodia, China, Cyprus, Georgia*, India, Indonesia, Iran, Iraq, Israel, Japan, Jordan, Kazakhstan*, North Korea, South Korea, Kuwait, Kyrgyzstan, Laos, Lebanon, Malaysia, Maldives, Mongolia, Nepal, Oman, Pakistan, Philippines, Qatar, Russia*, Saudi Arabia, Singapore, Sri Lanka, Syria, Tajikistan, Thailand, Timor-Leste, Turkey*, Turkmenistan, United Arab Emirates, Uzbekistan, Vietnam, Yemen (* indicates part of the country is also in Europe);

North America (23): Antigua and Barbuda, The Bahamas, Barbados, Belize, Canada, Costa Rica, Cuba, Dominica, Dominican Republic, El Salvador, Grenada, Guatemala, Haiti, Honduras, Jamaica, Mexico, Nicaragua, Panama, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Trinidad and Tobago, United States;

Oceania (14): Australia, Fiji, Kiribati, Marshall Islands, Federated States of Micronesia, Nauru, New Zealand, Palau, Papua New Guinea, Samoa, Solomon Islands, Tonga, Tuvalu, Vanuatu;

South America (12): Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Guyana, Paraguay, Peru, Suriname, Uruguay, Venezuela

land area about 16 times the size of the US

top fifteen World Factbook entities ranked by size: 155,557,000 Pacific Ocean; 76,762,000 Atlantic Ocean; 68,556,000 Indian Ocean; 20,327,000 Southern Ocean; 17,098,242 Russia; 14,056,000 Arctic Ocean; 14,000,000 Antarctica; 9,984,670 Canada; 9,826,675 United States; 9,596,960 China; 8,515,770 Brazil; 7,741,220 Australia; 4,324,782 European Union; 3,287,263 India; 2,780,400 Argentina

top ten largest water bodies: 155,557,000 Pacific Ocean; 76,762,000 Atlantic Ocean; 68,556,000 Indian Ocean; 20,327,000 Southern Ocean; 14,056,000 Arctic Ocean; 4,184,100 Coral Sea; 3595900 South China Sea; 2,834,000 Caribbean Sea; 2,520,000 Bering Sea; 2,469,000 Mediterranean Sea

top ten largest landmasses: 44,568,500 Asia; 30,065,000 Africa; 24,473,000 North America; 17,819,000 South America; 14,000,000 Antarctica; 9,948,000 Europe; 7,741,220 Australia; 2,166,086 Greenland; 785,753 New Guinea; 751,929 Borneo

top ten largest islands: 2,166,086 Greenland; 785,753 New Guinea (Indonesia, Papua New Guinea); 751,929 Borneo (Brunei, Indonesia, Malaysia); 587,713 Madagascar; 507,451 Baffin Island (Canada); 472,784 Sumatra (Indonesia); 227,963 Honshu (Japan); 217,291 Victoria Island (Canada); 209,331 Great Britain (United Kingdom); 196,236 Ellesmere Island (Canada)

ten smallest independent countries: 0.44 Holy See (Vatican City); 2 Monaco; 21 Nauru; 26 Tuvalu; 61 San Marino; 160 Liechtenstein; 181 Marshall Islands; 261 Saint Kitts and Nevis; 298 Maldives; 316 Malta

large areas subject to severe weather (tropical cyclones); natural disasters (earthquakes, landslides, tsunamis, volcanic eruptions)

volcanism: volcanism is a fundamental driver and consequence of plate tectonics, the physical process reshaping the Earth's lithosphere; the world is home to more than 1,500 potentially active volcanoes, with over 500 of these having erupted in historical times; an estimated 500 million people live near these volcanoes; associated dangers include lava flows, lahars (mudflows), pyroclastic flows, ash clouds, ash fall, ballistic projectiles, gas emissions, landslides, earthquakes, and tsunamis; in the 1990s, the International Association of Volcanology and Chemistry of the Earth's Interior, created a list of 16 Decade Volcanoes worthy of special study because of their great potential for destruction: Avachinsky-Koryaksky (Russia), Colima (Mexico), Etna (Italy), Galeras (Colombia), Mauna Loa (United States), Merapi (Indonesia), Nyiragongo (Democratic Republic of the Congo), Rainier (United States), Sakurajima (Japan), Santa Maria (Guatemala), Santorini (Greece), Taal (Philippines), Teide (Spain), Ulawun (Papua New Guinea), Unzen (Japan), Vesuvius (Italy); see second note under "Geography - note"

note: the world is now thought to be about 4.55 billion years old, just about one-third of the 13.8-billion-year age estimated for the universe

note: although earthquakes can strike anywhere at any time, the vast majority occur in three large zones of the earth; the world's greatest earthquake belt, the Circum-Pacific Belt (popularly referred to as the Ring of Fire), is the zone of active volcanoes and earthquake epicenters bordering the Pacific Ocean; about 90% of the world's earthquakes (81% of the largest earthquakes) and some 75% of the world's volcanoes occur within the Ring of Fire; the belt extends northward from Chile, along the South American coast, through Central America, Mexico, the western US, southern Alaska and the Aleutian Islands, to Japan, the Philippines, Papua New Guinea, island groups in the southwestern Pacific, and New Zealand

the second prominent belt, the Alpide, extends from Java to Sumatra, northward along the mountains of Burma, then eastward through the Himalayas, the Mediterranean, and out into the Atlantic Ocean; it accounts for about 17% of the world's largest earthquakes; the third important belt follows the long Mid-Atlantic Ridge

The international financial crisis of 2008-09 led to the first downturn in global output since 1946 and presented the world with a major new challenge: determining what mix of fiscal and monetary policies to follow to restore growth and jobs, while keeping inflation and debt under control. Financial stabilization and stimulus programs that started in 2009-11, combined with lower tax revenues in 2009-10, required most countries to run large budget deficits. Treasuries issued new public debt - totaling $9.1 trillion since 2008 - to pay for the additional expenditures. To keep interest rates low, most central banks monetized that debt, injecting large sums of money into their economies - between December 2008 and December 2013 the global money supply increased by more than 35%. Governments are now faced with the difficult task of spurring current growth and employment without saddling their economies with so much debt that they sacrifice long-term growth and financial stability. When economic activity picks up, central banks will confront the difficult task of containing inflation without raising interest rates so high they snuff out further growth.

Fiscal and monetary data for 2013 are currently available for 180 countries, which together account for 98.5% of world GDP. Of the 180 countries, 82 pursued unequivocally expansionary policies, boosting government spending while also expanding their money supply relatively rapidly - faster than the world average of 3.1%; 28 followed restrictive fiscal and monetary policies, reducing government spending and holding money growth to less than the 3.1% average; and the remaining 70 followed a mix of counterbalancing fiscal and monetary policies, either reducing government spending while accelerating money growth, or boosting spending while curtailing money growth.

(For more information, see attached spreadsheet.)

In 2013, for many countries the drive for fiscal austerity that began in 2011 abated. While 5 out of 6 countries slowed spending in 2012, only 1 in 2 countries slowed spending in 2013. About 1 in 3 countries actually lowered the level of their expenditures. The global growth rate for government expenditures increased from 1.6% in 2012 to 5.1% in 2013, after falling from a 10.1% growth rate in 2011. On the other hand, nearly 2 out of 3 central banks tightened monetary policy in 2013, decelerating the rate of growth of their money supply, compared with only 1 out of 3 in 2012. Roughly 1 of 4 central banks actually withdrew money from circulation, an increase from 1 out of 7 in 2012. Growth of the global money supply, as measured by the narrowly defined M1, slowed from 8.7% in 2009 and 10.4% in 2010 to 5.2% in 2011, 4.6% in 2012, and 3.1% in 2013. Several notable shifts occurred in 2013. By cutting government expenditures and expanding money supplies, the US and Canada moved against the trend in the rest of the world. France reversed course completely. Rather than reducing expenditures and money as it had in 2012, it expanded both. Germany reversed its fiscal policy, sharply expanding federal spending, while continuing to grow the money supply. South Korea shifted monetary policy into high gear, while maintaining a strongly expansionary fiscal policy. Japan, however, continued to pursue austere fiscal and monetary policies.

Austere economic policies have significantly affected economic performance. The global budget deficit narrowed to roughly $2.7 trillion in 2012 and $2.1 trillion in 2013, or 3.8% and 2.5% of World GDP, respectively. But growth of the world economy slipped from 5.1% in 2010 and 3.7% in 2011, to just 3.1% in 2012, and 2.9% in 2013.

Countries with expansionary fiscal and monetary policies achieved significantly higher rates of growth, higher growth of tax revenues, and greater success reducing the public debt burden than those countries that chose contractionary policies. In 2013, the 82 countries that followed a pro-growth approach achieved a median GDP growth rate of 4.7%, compared to 1.7% for the 28 countries with restrictive fiscal and monetary policies, a difference of 3 percentage points. Among the 82, China grew 7.7%, Philippines 6.8%, Malaysia 4.7%, Pakistan and Saudi Arabia 3.6%, Argentina 3.5%, South Korea 2.8%, and Russia 1.3%, while among the 28, Brazil grew 2.3%, Japan 2.0%, South Africa 2.0%, Netherlands -0.8%, Croatia -1.0%, Iran -1.5%, Portugal -1.8%, Greece -3.8%, and Cyprus -8.7%.

Faster GDP growth and lower unemployment rates translated into increased tax revenues and a less cumbersome debt burden. Revenues for the 82 expansionary countries grew at a median rate of 10.7%, whereas tax revenues fell at a median rate of 6.8% for the 28 countries that chose austere economic policies. Budget balances improved for about three-quarters of the 28, but, for most, debt grew faster than GDP, and the median level of their public debt as a share of GDP increased 9.1 percentage points, to 59.2%. On the other hand, budget balances deteriorated for most of the 82 pro-growth countries, but GDP growth outpaced increases in debt, and the median level of public debt as a share of GDP increased just 1.9%, to 39.8%.

The world recession has suppressed inflation rates - world inflation declined 1.0 percentage point in 2012 to about 4.1% and 0.2 percentage point to 3.9% in 2013. In 2013 the median inflation rate for the 82 pro-growth countries was 1.3 percentage points higher than that for the countries that followed more austere fiscal and monetary policies. Overall, the latter countries also improved their current account balances by shedding imports; as a result, current account balances deteriorated for most of the countries that pursued pro-growth policies. Slow growth of world income continued to hold import demand in check and crude oil prices fell. Consequently, the dollar value of world trade grew just 1.3% in 2013.

Beyond the current global slowdown, the world faces several long standing economic challenges. The addition of 80 million people each year to an already overcrowded globe is exacerbating the problems of pollution, waste-disposal, epidemics, water-shortages, famine, over-fishing of oceans, deforestation, desertification, and depletion of non-renewable resources. The nation-state, as a bedrock economic-political institution, is steadily losing control over international flows of people, goods, services, funds, and technology. The introduction of the euro as the common currency of much of Western Europe in January 1999, while paving the way for an integrated economic powerhouse, has created economic risks because the participating nations have varying income levels and growth rates, and hence, require a different mix of monetary and fiscal policies. Governments, especially in Western Europe, face the difficult political problem of channeling resources away from welfare programs in order to increase investment and strengthen incentives to seek employment. Because of their own internal problems and priorities, the industrialized countries are unable to devote sufficient resources to deal effectively with the poorer areas of the world, which, at least from an economic point of view, are becoming further marginalized. The terrorist attacks on the US on 11 September 2001 accentuated a growing risk to global prosperity - the diversion of resources away from capital investments to counter-terrorism programs.

Despite these vexing problems, the world economy also shows great promise. Technology has made possible further advances in a wide range of fields, from agriculture, to medicine, alternative energy, metallurgy, and transportation. Improved global communications have greatly reduced the costs of international trade, helping the world gain from the international division of labor, raise living standards, and reduce income disparities among nations. Much of the resilience of the world economy in the aftermath of the financial crisis resulted from government and central bank leaders around the globe working in concert to stem the financial onslaught, knowing well the lessons of past economic failures.

the whole range of industrial and agricultural goods and services

top ten - share of world trade: 14.8 electrical machinery, including computers; 14.4 mineral fuels, including oil, coal, gas, and refined products; 14.2 nuclear reactors, boilers, and parts; 8.9 cars, trucks, and buses; 3.5 scientific and precision instruments; 3.4 plastics; 2.7 iron and steel; 2.6 organic chemicals; 2.6 pharmaceutical products; 1.9 diamonds, pearls, and precious stones

the whole range of industrial and agricultural goods and services

top ten - share of world trade: see listing for exports

three major data centers - which provide colocation, telecommunications, cloud services, and content ecosystems - compete to be called the world's biggest in terms of physical space occupied:

no. 1. - a data farm in Langfang, Hebei Province, China, identified as the Range International Information Group, claims to be the largest with 585,000 sq m (6.3 million sq ft),

no. 2. - a data farm in Las Vegas, Nevada, USA, known as the Switch SuperNAP data center, comes in second with over 325,000 sq m (3.5 million sq ft); it intends to expand to over 1.615 million sq m (17.4 million sq ft) by 2020,

no. 3. - a data farm in Ashburn, Virginia, USA, referred to as the DFT Data Center, is a transit point for 70% of the world's Internet traffic; it includes 150,000 sq m (1.6 million sq ft) spread out over six separate buildings

the International Maritime Bureau (IMB) reports that 2017 saw a continued slight decrease in global pirate activities; in 2017, pirates attacked a total of 180 ships world-wide including boarding 136 ships, hijacking six ships, and firing on 16; this activity is down from 191 incidents in 2016; in 2017, the number of hostages dropped to 91, however, the number of seafarers kidnapped for ransom increased dramatically to 75 with nearly all taken off West Africa; three mariners were killed world-wide in 2017

Operation Ocean Shield, the NATO naval task force established in 2009 to combat Somali piracy, concluded its operations in December 2016 as a result of the drop in reported incidents over the last few years; the EU naval mission, Operation ATALANTA, continues its operations in the Gulf of Aden and Indian Ocean through 2020; naval units from Japan, India, and China also operate in conjuction with EU forces; China has established a logistical base in Djibouti to support its deployed naval units in the Horn of Africa

the Horn of Africa continued to see pirate activities with 12 incidents in 2017, a slight increase over 2016; the decrease in successful pirate attacks off the Horn of Africa since the peak in 2007 was due, in part, to anti-piracy operations by international naval forces, the hardening of vessels, and the increased use of armed security teams aboard merchant ships; despite these preventative measures, the assessed risk remains high

West African piracy is a continuing threat with 33 attacks in 2017 compared to 36 in 2016; Nigerian pirates are very aggressive, operating as far as 200 nm offshore and boarding 20 ships in 2017; attacks in South Asian waters remain at low levels with an increase in Bangladesh from three incidents in 2016 to 11 in 2017; Peru reported two incidents in 2017, down from 11 in 2016; attacks in Vietnam declined from nine in 2016 to two in 2017; the majority of global attacks against shipping have occured in the offshore waters of five countries - Nigeria, Indonesia, Philippines, Venezuela, and Bangladesh

cocaine: worldwide coca leaf cultivation in 2013 likely amounted to 165,000 hectares, assuming a stable crop in Bolivia; Colombia produced slightly less than half of the worldwide crop, followed by Peru and Bolivia; potential pure cocaine production increased 7% to 640 metric tons in 2013; Colombia conducts an aggressive coca eradication campaign, Peru has increased its eradication efforts, but remains hesitant to eradicate coca in key growing areas;

opiates: worldwide illicit opium poppy cultivation increased in 2013, with potential opium production reaching 6,800 metric tons; Afghanistan is world's primary opium producer, accounting for 82% of the global supply; Southeast Asia was responsible for 12% of global opium; Pakistan produced 3% of global opium; Latin America produced 4% of global opium, and most was refined into heroin destined for the US market