Every time the Olympics invades a city, its topography is transformed by an influx of impressive new buildings erected for the event. In the case of London, most will eventually be torn down. It's an incredible feat of design and engineering to build structures that can be both quickly built and disassembled. In this video the architects behind the Olympic Stadium, 377-foot Orbit observation tower, and the Coca-Cola-sponsored Beatbox installation describe their concepts. [Crane.tv via Selectism]