Short answer: Ceilings.
Long answer: Ceilings have devolved from being the focal point of a room to being a zone for mechanical equipment. In all the world’s greatest spaces we’ve always looked up in awe. Where our gaze was once met with fantastical vaulted ceilings, remarkable truss structures, or distinctive decorative treatments, today we typically find acoustic tiles, ductwork, and fluorescent strip lighting. Having abandoned the ceiling as a canvas for creativity with the dawn of the technological era, we’ve had a hard time taking it back. Today, it’s hard to compete with all that mechanical equipment when all you’re arguing for is a blank white surface. But a compelling vision of a space designed to make the ceiling its primary feature can enchant even the most pragmatic minds. There is good reason to be stubborn: since we seldom rearrange or redecorate the ceiling the way we do the rest of a space, what we create overhead lives a long life.