Besides being an island of Britain, Great Britain is an island nation in Europe that is surrounded by the Atlantic Ocean.
It is off the coast of the English Channel by France. It contains four British states like Scotland, Wales, England (the three parts that are part of Britain), and Northern Ireland (the only part in the UK that shares another border with another country; Ireland).
It is also the country of royalty. Fully known as the UK, the United Kingdom, or the United Kingdom of Great Britain and Northern Ireland, the capital and largest city of Great Britain is London, which is also the capital of England. It is located on the River Thames. London is known to have many landmarks like Big Ben (the name applied to the bell and not the clock tower, which is really called the Elizabeth Tower), Houses of Parliament, Tower Bridge, Buckingham Palace, and other famous landmarks.
When Timmy Turner wished the Founding Fathers to be brought to help him finish his History report, America reverted back to being a British colony and turned into a London-like town. It was undone when Timmy and the Founding Fathers travel back to the 18th Century in order to prevent Benedict Arnold from creating the alternate future and force the other delegates from the Continental Congress to surrender.
In Abra-Catastrophe!, Bippy got hold of Timmy's Magic Muffin and wished everything in the world ruled by Apes, turning all the world cities, including London, into a jungle. After everything went back to normal, Crocker got the muffin and captured Wanda in order to make himself ruler of the universe, turning everything into the world of his own before Timmy wished everything back to normal once Crocker has been defeated.
In The Jerkinators!, while Timmy and Jimmy Neutron were trying to figure out some ways to make Shirley "the greatest villain of all time," they play golf that sends him crashing in the Palace of Westminister.