The Moravian Pottery & Tile Works Museum is a funky-looking building that I'd driven past for years while growing up and living in the greater Philadelphia area. I finally took the time to stop and take some photos.
A National Historic Landmark, the Tile Works is a structure made entirely out of poured concrete and maintained as a "working history" museum by the Bucks County Department of Parks & Recreation. Beautiful handmade tiles are still produced there using methods similar to those when it was founded.
The museum itself is great, but for a totally different experience, go back after hours and just walk the grounds which you'll have completely to yourself. The building and its surroundings when deserted have an other-worldliness that's difficult to describe.