North, East, South, West, Michael Heizer, 1967/2002. Dia Art Foundation.

In addition to rotating exhibits, Dia also has several works on permanent view. This includes the above piece by Michael Helzer, which gives visitors the feeling of an endless drop when viewed from the right angle. Though roped off for safety reasons, those lucky enough to be allowed past can experience a jarring optical illusion that displaces the senses, while also creating a sense of aesthetic wonder.  Photo 6 of 27 in Weekend Detour: Beacon, New York