Tokyo is known as the most populated city on Earth. Actually 23 municipalities(special wards) make up the core of the city of Tokyo. The official population of City of Tokyo(23 special wards) is less than 10 million, which should be less populated than Seoul, Shanghai, Mumbai, Delhi or Mexico city but the metropolitan area of Tokyo is more than 37 million inhabitants and it is the biggest in the world. Other major cities over 1 million inhabitants in the metropolitan area are Yokohama, Kawasaki and Saitama.
Tokyo metropolis(which does not included above three major cities. These cities belong to different prefectures) also includes smaller cities in Tama area and outlying islands in the Pacific; Izu islands and Ogasawara islands. The most southern point of Japan is Okinotori island and most eastern point Minamitori island also belongs to Tokyo metropolis, which is governed by Tokyo metropolitan government.
The history of Tokyo started in 1457 as a tiny fishing village. However the status has changed in 1603 when the feudal warlord, the head of Tokugawa clan, Ieyasu Tokugawa decided to live at Edo castle as the seat of Tokugawa shogunate, de facto capital of Japan. At that time, the city was called Edo and emperors lived in Kyoto. In 1721, the population of Edo passed 1 million and became the biggest city on Earth.
Then, Tokugawa shogunate decided to resign to rule Japan in 1868 and name has changed from Edo to Tokyo - Capital of East. The emperor Meji moved his residence to Tokyo also in 1868 and Tokyo has finally became the official capital of Japan.
The city has faced two tragedies. The first one is the big earthquake in 1923 and WW2. Almost whole Tokyo was in ruin but dramatically rebuilt after these incidents.
Tokyo hosted summer Olympic games in 1964 and it is going to host again in 2020.