Tomorrow Square is the eighth-tallest building in Shanghai, China. It is located in Huangpu District, Puxi, close to People's Square. It is about 285 m (934 ft) tall and has 63 floors. This multi-purpose building contains a 342-room JW Marriott hotel, and 255 executive apartment units. It was completed on 1 October 2003. Starting from a square base, the all-concrete Tomorrow Square tower transforms itself into a diagonal square as it rises to a peak. Engineers of the exterior vertical support system were faced with a unique challenge as a result of this unusual shape. They chose flat slabs for the hotel floors and beam and slab construction for the office floors. A combination of shear walls and frame action stabilizes the slender tower laterally against wind and earthquake forces. The foundations are 80 m-long bored piles supporting a column mat.