Tokyo is Japan's capital and the world's most populous metropolis. It is also one of Japan's 47 prefectures, consisting of 23 central city wards and multiple cities, towns and villages west of the city center. The lzu and Ogasawara Islands are also part of Tokyo.
Tokyo is often referred to and thought of as a city, but is officially known as a "metropolitan prefecture", which differs from a city. The Tokyo metropolitan government administers the 23 Special Wards of Tokyo (each governed as an individual city), which cover the area that was formerly the City of Tokyo before it merged and became the subsequent metropolitan prefecture in 1943. The metropolitan government also administers 39 municipalities in the western part of the prefecture and the two outlying island chains. The population of the special wards is over 9 million people, with the total population of the prefecture exceeding 13 million. The prefecture is part of the world's most populous metropolitan area with upwards of 35 million people and the world's largest urban agglomeration economy with a GDP of US$1.479 trillion at purchasing power parity, ahead of the New York metropolitan area in 2008. The city hosts 51 of the Fortune Global 500 companies, the highest number of any city.
Today, Tokyo offers a seemingly unlimited choice of shopping, entertainment, culture and dining to its visitors. The city's history can be appreciated in districts such as Asakusa, and in many excellent museums, historic temples and gardens. Contrary to common perception, Tokyo also offers a number of attractive green spaces in the city center and within relatively short train rides at its outskirts.
Prior to 1868, Tokyo was known as Edo. A small castle town in the 16th century, Edo became Japan's political center in 1603 when Tokugawa leyasu established his feudal government there. A few decades later, Edo had grown into one of the world's most populous cities. With the Meiji Restoration of 1868, the emperor and capital moved from Kyoto to Edo, which was renamed Tokyo ("Eastern Capital"). Large parts of Tokyo were destroyed in the Great Kanto Earthquake of 1923 and in the air raids of 1945.