Fujimi Tower is the only three-story tower remaining in Edo Castle.

It was once the largest castle tower in Japan, but now only the stone walls of the castle tower base remain.

It can generally be visited within the Imperial Palace East Outer Gardens of Edo Castle Honmaru, Ninomaru, and Sannomaru.

The Yasakani no Magatama, one of the Three Sacred Treasures, is enshrined in the Imperial Palace's Kenji-no-Matama Room. The Sacred Treasures are treated as sacred objects and are not open to the public. Even the Emperor does not usually see the real thing. 

[Trivia]
The real Three Sacred Treasures cannot be seen by the general public. The Yata no Kagami is enshrined at Ise Shrine, the Kusanagi no Tsurugi at Atsuta Shrine, and the Yasakani no Magatama in the Imperial Palace's Kenji-no-Matama Room, and even the Emperor rarely sees them in person.