If you intend to visit Osaka, I would recommend going to the district of Shin Umeda City. There is one particular point of interest: Umeda Sky Building, built in 1993 by Hiroshi Hara. This huge building has a very special architecture, as it consists of two 40-story towers connected by a circular observatory.
First, have a break in the Floating Garden Observatory from where you can admire the city behind huge windows. Going up some stairs, you find yourself out on the stunning Lumi Sky Walk which describes a phosphorescent milky way to the ground. The 360-degree aerial views of Osaka are absolutely stunning, especially at dusk and at night.
Umeda Sky Building: from 10am to 10:30pm, ¥700 entry fee for adults.