Geographic overview In 18 editions of 36.

The surface of the Earth is approximately 70.9% water and 29.1% land. The water portion is the World Ocean, the single largest feature of the planet and one that connects all places on the globe. The continental landmasses divide this ocean into five major ocean basins, which are (in decreasing order of size) the Pacific, Atlantic, Indian, Southern, and Arctic. The World Factbook describes these five as oceans. Because of the major ocean currents and the effects of the major air masses above them, 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, creating seven major water bodies -- the so-called "Seven Seas."

About 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 mountain glaciers and the Antarctic ice sheets. If all the surface ice on earth fully melted, the sea level would rise about 70 m (230 ft).

Earth's land portion is divided into landmasses called continents. Different continental definitions are recognized in certain parts of the world, with some more heavily based on culture than physical geography.

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, and North and South America are sometimes grouped as the Americas, with either usage resulting in a continent total of six (or five, if both are used).

North America is commonly understood to include Greenland and the Caribbean islands and to extend south to the Isthmus of Panama. The Ural Mountains and the Ural River are usually considered the easternmost part of Europe, the Caspian Sea is the limit to the southeast, and the Caucasus Mountains, the Black Sea, and the Mediterranean to the south. Asia usually incorporates all the islands of the Philippines, Malaysia, and Indonesia.

The Pacific islands are often lumped with Australia and designated as 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.

In total, the United States recognizes 197 countries. Using the seven-continent model and grouping islands with adjacent continents, Africa has the most countries with 54. Europe has 49 countries and Asia 48, with five countries shared: Azerbaijan, Georgia, Kazakhstan, Russia, and Turkey. North America has 23, Oceania has 16, and South America has 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,
• Malta,
• Moldova,
• Monaco,
• Montenegro,
• Netherlands,
• North Macedonia,
• 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 (16):

• Australia,
• Cook Islands,
• Fiji,
• Kiribati,
• Marshall Islands,
• Federated States of Micronesia,
• Nauru,
• New Zealand,
• Niue,
• 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

Three of the states described above – France, Netherlands, and the United Kingdom – consist of smaller political entities that are referred to as countries. France considers French Polynesia an overseas country; the Kingdom of the Netherlands refers to all four of its constituent parts (the Netherlands and the islands of Aruba, Curacao, and Sint Maarten) as countries; and the United Kingdom is composed of the countries of England, Wales, Scotland, and Northern Ireland.

the World from space:

Earth is the only planet in the solar system to have water in its three states of matter: liquid (oceans, lakes, and rivers), solid (ice), and gas (water vapor in clouds). From a distance, Earth would be the brightest of the eight planets in the solar system because of the planet's water reflecting sunlight.

Earth has a slight equatorial bulge -- a difference between its equatorial and polar diameters -- because of the centrifugal force from the planet rotating on its axis. The equatorial diameter is 12,756 km, but the polar diameter is 12,714 km; the circumference at the equator is 40,075 km, and the polar circumference is 40,008 km.