So we've already taken a look at two "City within a city" areas so far - Roppongi Hills and Tokyo Midtown. Went to another one just outside Tokyo Station called Shin Marunouchi Building - a building indeed it is but a city lies within.
BTW, this image is in the wallpaper pool together with the Gurren photo of Yoko that you asked for ^^
BTW2, I'm going to be deleting images from the wallpaper pool soon so get them while you can.