defeated at the Battle of Culloden in 1746, after which the Scottish Highlanders were brutally suppressed. The British colonies in North America that broke away from Britain in the American War of Independence became the United States of America, recognised by Britain in 1783. British imperial ambition turned towards Asia, particularly to India. Britain played a leading part in the Atlantic slave trade, mainly between 1662 and 1807 when British or British-colonial Slave ships transported nearly 3.3 million slaves from Africa. The slaves were taken to work on plantations in British possessions, principally in the Caribbean but also North America. Slavery coupled with the Caribbean sugar industry had a significant role in strengthening and developing the British economy in the 18th century. However, Parliament banned the trade in 1807, banned slavery in the British Empire in 1833, and Britain took a role in the movement to abolish slavery worldwide through the blockade of Africa and pressing other nations to end their trade with a series of treaties. United Kingdom of Great Britain and Ireland The term "United Kingdom" became official in 1801 when the parliaments of Great Britain and Ireland each passed an Act of Union, uniting the two kingdoms and creating the United Kingdom of Great Britain and Ireland. After the defeat of France at the end of the French Revolutionary Wars and Napoleonic Wars (1792–1815), the United Kingdom emerged as the principal naval and imperial power of the 19th century (with London the largest city in the world from about 1830). Unchallenged at sea, British dominance was later described as Pax Britannica ("British Peace"), a period of relative peace among the Great Powers (1815–1914) during which the British Empire became the global hegemon and adopted the role of global policeman. By the time of the Great Exhibition of 1851, Britain was described as the "workshop of the world". From 1853 to 1856, Britain took part in the Crimean War, allied with the Ottoman Empire in the fight against the Russian Empire, participating in the naval battles of the Baltic Sea known as the Åland War in the Gulf of Bothnia and the Gulf of Finland, among others. The British Empire was expanded to include India, large parts of Africa and many other territories throughout the world. Alongside the formal control it exerted over its own colonies, British dominance of much of world trade meant that it effectively controlled