United Kingdom

The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK, or Britain, is a sovereign island country located off the northwestern coast of mainland Europe. The UK includes the island of Great Britain, the northeast part of the island of Ireland and many small islands. Northern Ireland is the only part of the UK with a land border, sharing it with the Republic of Ireland. Apart from this land border, the UK is surrounded by the Atlantic Ocean, the North Sea, the English Channel and the Irish Sea. The largest island, Great Britain, is linked to France by the Channel Tunnel.
The United Kingdom is a union of four constituent countries: England, Northern Ireland, Scotland and Wales. The United Kingdom is governed by a Parliamentary System with its seat of government in London, the capital, and a constitutional monarchy with Her Majesty Queen Elizabeth II as the head of state. The Crown Dependencies of the Channel Islands and the Isle of Man, formally possessions of the Crown, are not part of the UK but form a federacy with it. The UK has fourteen overseas territories,all remnants of the British Empire, which at its height encompassed almost a quarter of the world's land surface, making it the largest empire in history. As a direct result of the empire, British influence can be observed in the language and culture of states such as Canada, Australia, New Zealand, India, Pakistan, South Africa, Singapore, Sri Lanka and the United States of America, and other less globally influential independent states. HM Queen Elizabeth II remains the head of the Commonwealth of Nations and head of state of each of the Commonwealth realms.
The UK is a developed country, with the fifth (nominal GDP) or sixth (PPP) largest economy in the world. It was the world's foremost power during the 19th and early 20th century,but the economic cost of two world wars and the decline of its empire in the latter half of the 20th century diminished its leading role in global affairs. The UK nevertheless retains strong economic, cultural, military and political influence and is a nuclear power, with the second or third (depending on method of calculation) highest defence spending in the world. It is a member state of the European Union, holds a permanent seat on the United Nations Security Council, and is a member of the G8, NATO, WTO and the Commonwealth of Nations.

Australia

The Commonwealth of Australia is a country in the southern hemisphere comprising the mainland of the world's smallest continent, the major island of Tasmania, and numerous other islands in the Indian and Pacific Oceans. The neighboring countries are Indonesia, East Timor, and Papua New Guinea to the north, the Solomon Islands, Vanuatu, and New Caledonia to the northeast and New Zealand to the southeast. Australia is the only country that is also a continent.
The Australian mainland has been inhabited for more than 42,000 years by indigenous Australians. After sporadic visits by fishermen from the north and then European discovery by Dutch explorers in 1606, the eastern half of Australia was later claimed by the British in 1770 and initially settled through penal transportation to the colony of New South Wales, commencing on 26 January 1788. As the population grew and new areas were explored, another five largely self-governing Crown Colonies were established during the 19th century.
On 1 January 1901, the six colonies became a federation, and the Commonwealth of Australia was formed. Since federation, Australia has maintained a stable liberal democratic political system and remains a Commonwealth realm. The capital city is Canberra, located in the Australian Capital Territory (ACT). The population is just over 21.3 million, with approximately 60% of the population concentrated in and around the mainland state capitals of Sydney, Melbourne, Brisbane, Perth, and Adelaide.

United States of America

The United States of America is a constitutional federal republic comprising fifty states and a federal district. The country is situated mostly in central North America, where its forty-eight contiguous states and Washington, D.C., the capital district, lie between the Pacific and Atlantic Oceans, bordered by Canada to the north and Mexico to the south. The state of Alaska is in the northwest of the continent, with Canada to its east and Russia to the west across the Bering Strait, and the state of Hawaii is an archipelago in the mid-Pacific. The United States also possesses several territories, or insular areas, scattered around the Caribbean and Pacific.
At 3.79 million square miles (9.83 million km²) and with more than 300 million people, the United States is the third or fourth largest country by total area, and third largest by land area and by population. The United States is one of the world's most ethnically diverse nations, the product of large-scale immigration from many countries. The U.S. economy is the largest national economy in the world, with a nominal 2006 gross domestic product (GDP) of more than US$13 trillion (over 19% of the world total based on purchasing power parity).
The nation was founded by thirteen colonies of Great Britain located along the Atlantic seaboard. Proclaiming themselves "states," they issued the Declaration of Independence on July 4, 1776. The rebellious states defeated Great Britain in the American Revolutionary War, the first successful colonial war of independence. A federal convention adopted the current United States Constitution on September 17, 1787; its ratification the following year made the states part of a single republic. The Bill of Rights, comprising ten constitutional amendments, was ratified in 1791.
In the nineteenth century, the United States acquired land from France, Spain, the United Kingdom, Mexico, and Russia, and annexed the Republic of Texas and the Republic of Hawaii. Disputes between the agrarian South and industrial North over states' rights and the expansion of the institution of slavery provoked the American Civil War of the 1860s. The North's victory prevented a permanent split of the country and led to the end of slavery in the United States. The Spanish-American War and World War I confirmed the nation's status as a military power. In 1945, the United States emerged from World War II as the first country with nuclear weapons, a permanent member of the United Nations Security Council, and a founding member of NATO. In the post–Cold War era, the United States is the only remaining superpower—accounting for approximately 50% of global military spending—and the dominant economic, political, and cultural force in the world.