I was surprised to discover that a new tower is being built right now in the heart of Tokyo : the Tokyo Sky Tree (東京スカイツリー, Tōkyō Sukai Tsurī). First called New Tokyo Tower, this goal of this tower is, indeed, to replace the famous Tokyo Tower (東京タワー, 332.5 meters built in 1958) as a broadcasting device for the capital.
This tower is being built in Sumida, and will have a height of 634 meters. Taken from
Wikipedia, the picture is a computer-rendered picture of the view we will have once the structure is finished.
There will be two observation platforms at 350 and 450 meters. Upon completion, it will be the tallest structure in Japan - a title still held by the Tokyo Tower, which is also the tallest free-standing steel structure in the world. Construction began in 2008 and completion is expected in 2011, with public access in the spring of 2012. It was designed by the famous architect Tadao Ando.
This tower already has a web site in English :
www.tokyo-skytree.jp/english