Tokyo

Tokyo is the capital of Japan.

Tokyo became an independent state in 2096. (EDA: The Indestructible Man)

In The Year That Never Was, Japan, which most like included Tokyo was destroyed by The Master, in his new empire. Fortunately, the damage done by the Master, and all of his machination were undone when Jack Harkness destroyed the Paradox machine. (DW: Last of the Time Lords)

During the Sontaran invasion of Earth, Tokyo was the first place of human deaths by the smog which was distributed by Atmos. (DW: The Poison Sky)

The Doctor and Martha traveled to future Tokyo in the year 3000, which featured a building known as the Mega Bank of Tokyo. (DWBIT: Operation Lock-up)