Shinjuku can definitely be said to be one of the most important areas in the extremely busy city of Tokyo.
When talking about Shinjuku, you can never avoid speaking about Shinjuku Station. Ranked by the Guinness Book of World Records as the busiest station in the world, it is used by 3,640,000 people daily. It is one of the terminal stations for many lines, and an important station for transporting people throughout Tokyo. The Odakyu Line, JR Chuo Line, JR Yamanote Line, and Saikyo Line are just some examples of the trains that run to and from Shinjuku Station. As you can see, this is a station only for the important lines in Tokyo. However, it is not a station for bullet trains.
Stepping out of Shinjuku Station is, without a doubt, interesting as well. Outside of the South Exit, you will first see Docomo Tower, the third tallest tower in Tokyo Prefecture (please be aware that there is no observatory). Shinjuku Takashimaya, one of the major department stores in Japan is also there as well. Step out of the West Exit, and you will see various electronics stores and numerous office buildings. This area is, compared to other areas of Shinjuku, mainly for businessmen. At the East Exit of Shinjuku, the famous Kabuki-cho district will appear. This area is famous for having many nightclubs and izakayas (Japanese drinking spots). At night, many people gather here to enjoy partying with their friends or colleagues. Thus, it can definitely be said that there is never a time when Shinjuku is not busy.
It is never an exaggeration to say that you can afford anything you want in Shinjuku. Why not experience the busyness of Tokyo?