You can spend a lifetime in Tokyo and just barely scratch the surface of all the sites that can be visited. We went to the Meiji-Jingu Shrine (http://www.meijijingu.or.jp/english/index.html) which is a Shinto shrine located in the middle of Tokyo. It was created after the death of Emperor Meiji and Empress Shoken in 1912 and 1914, respectively. The people wanted to commemorate the virtuous life of the Emperor and his wife so over 100,000 trees were donated from all over the country and volunteers spent the next few years building a forest in the heart of Tokyo.
Regardless of which side of the forest you enter from, you will come across a Torii, or Shrine Archway. To show respect, you are supposed to bow when entering and again when leaving.