One of the most popular places to visit in Tokyo is Sensoji Temple in Asakusa. Last year and this year I stayed right by the temple (about 1-2 minutes walk). There’s something about starting and ending the day walking past this place. During the day it’s very crowded, with foreigners and Japanese people alike. At night it’s quiet and calm. Although the buildings are closed at this time it’s still interesting to see statues and such softly lit.
There’s info about the temple here if you wish to learn about it.