Yasukuni-jinja
On my first long walk around the neighborhood, I stumbled upon what I thought was part of the large park that surrounds the Imperial Palace. There were no signs that I could read, but there were a lot of Japanese people taking pictures so I followed them through a huge gateway into what I guessed was some sort of shrine. Behind the buildings I found a beautiful little koi pond surrounded by rocks and trees and benches where people were sitting and eating lunch. Later I discovered that the site is a very controversial shrine called Yasukuni-jinja.