A press preview for the newly completed commercial complex surrounding the 634-meter-high Tokyo Sky Tree in Tokyo's Sumida Ward was held Thursday. The 37,000-square-meter complex consists of a 312-tenant shopping and restaurant zone called ''Tokyo Solamachi,'' an office building zone, an aquarium and a planetarium. The Sumida Aquarium displays around 10,000 marine animals belonging to 400 species, including sea turtles, and features cisterns that represent ecological systems in the area from Tokyo Bay to the Ogasawara island chain, roughly a thousand kilometers south of central Tokyo. The office building zone incorporates a university campus of the Chiba Institute of Technology, at which a range of high technology items such as robots and a Mars probe are displayed. The complex was completed at the former railway freight car yard of Tobu Railway Co., the parent company of the operator of the world's tallest self-standing tower, which opens on May 22.