Tokyo is the largest metropolitan area in the world and I can tell you, that from my hotel in Shinjuku, it appears to go on as far as the eye can see. It is divided into 23 areas called wards. Within each ward are districts such as Ginza and Akihabara. The main business and financial districts are in the Marunouchi district. This is where Tokyo Station is so I think of it as downtown. However, the nations government is in the Nagatacho district and the city government is in the Shinjuku district, considered by many to be the center of Tokyo. The Imperial Palace is in the Chiyoda district close to Tokyo Station.
There is an almost endless amount of things to see and do in Tokyo. One place that I recommend everyone visit is:
Another must-see, especially for anime fans is:
If you only have time to visit one Shinto shrine—you must visit at least one—make it this one: