The Imperial Palace occupies the site of Edo Castle, which was the seat of the Tokugawa shogunate from 1603 to 1868. The palace buildings themselves are closed except on two public days a year, but the East Garden (Higashi Gyoen) is open to visitors and is one of the most beautiful formal gardens in Tokyo — ancient pines, traditional stone lanterns, reconstructed guardhouses, and the remains of the original castle foundations.
The outer gardens surrounding the palace, particularly the Kitanomaru Park and the broad gravel paths facing the Nijubashi bridge, are excellent for a morning walk. The sight of Tokyo's skyscrapers framing the palace's green moat is one of the defining images of the city. Subway: Nijubashimae (Chiyoda line) or Otemachi.