Squint a little, and the Hemeroscopium House, designed by Antón García-Abril, looks like a highway underpass. And in a certain way, it is: The house was built with girders and concrete beams. The huge concrete slab you see perched atop the house weighs 20 tons; its weight holds the house together, at its center of gravity–like a giant thumb pinning down a precarious Jenga stack.
Amazingly, the whole thing took just seven days to built, in a carefully choreographed sequence, carried off by huge construction cranes. Maybe the most dramatic gesture is a long, thin swimming pool, suspended in mid-air. Check out the pictures, and don’t miss the video of its construction, below.