Comic book stained glass windows and a colorful skateboard ramp space? Last April, Paris' Palais de Tokyo reopened its doors after spending an astounding $26 million during 10 months of renovations. Now the largest contemporary art center in Europe, the museum has four levels and is as big as three soccer fields. With so much space, they've creatively let the building itself become part of the art. For 12 to 18 month stints, artists are invited to actually paint or construct their works right onto the building's windows, stairways and even signs.