Tokyo station is the terminus for most shinkansen services and classic JR lines. The station is divided into two parts:
Marunouchi and
Yaesu.
A short walk north-west from the Marunouchi exit will lead you to the
Imperial Palace and the
Imperial Palace East Gardens. The palace is built on the site of the former Edo Castle. The palace was completed in 1888 and is now the residence of Emperor Akihito.
Most areas are not accessible to the public, but you can visit the East Gardens, which include a Japanese-style garden (Tues. - Thurs. and Sat. -Mon., 9 am - 4:30 pm, Nov-Feb, 4pm, free).
You can also walk to the
National Museum of Modern Art, which displays the largest collection of modern Japanese art as well as Western-style paintings (Tues. - Sun., 10 am to 5 pm, 8pm Fridays, ¥420).