London is the capital and largest city in England and the UK. It stands on a river in the southeastern part of England at the mouth of a 50-kilometer (80 km) bottom of the sea, and has been an important settlement for 2 years. The city of London, with its ancient and financial center, was founded by the Romans as Londinium and maintains borders close to ancient times. Since the 19th century, "London" has also designated a large city around the peninsula, historically divided between the states of Middlesex, Essex, Surrey, Kent, and Hertfordshire, which comprises the national capital, controlled by the Greater London Authority. The city of Westminster, west of London, has for centuries held the national government and parliament.

London, which is connected with cities around the world, has a strong influence on the arts, commerce, education, entertainment, fashion, finance, health care, the media, tourism, and communications, and as such has sometimes been called the capital of the world. Its GDP (801.66 billion by 2017) makes it Europe's largest urban economy, and one of the world's leading financial institutions. In 2019 it had the second highest number of people with the highest number in Europe after Paris and therefore the second highest number of billionaires in any European city after Moscow. With some of the best educational institutions in Europe, it includes Imperial College London in natural and applied sciences, the London School of Economics in social sciences, and University College London. the town is home to the top 5 star hotels of any city in the world. In 2012, London became the main city to host three Summer Olympics.