Poor Madrid. Not one, but two failed Olympic bids in a single decade. However, there is a silver lining. The city now has some tremendous new sporting venues. French architect Domiique Perrault designed the "Magic Box," the proposed Olympic Tennis Center. The structure is home to three tennis venues and employs a remarkable hydraulic roof. Hit the switch, and what appears as a single, unified piece breaks into three parts to form almost unlimited topographies. Pretty f'ing awesome. [Fast Co. Design]