In a city where space is at a premium, it’s not often you see abandoned buildings that aren’t about to be torn down to build new ones. Most of the ones you can see lie on the outer reaches of the boroughs. The abandoned smallpox clinic, otherwise known as the Renwick Ruin, however, can be found on Roosevelt Island, easily accessible by car, foot, rail, bus, ferry, and air tram. The narrow island itself is beautiful to roam around, but the smallpox clinic at the bottom of the island is my favorite spot.

The clinic is built to look like a castle, though it’s smaller than you would expect for a clinic. Most of the structure remains standing, though it lacks windows, doors, stairs, and a roof. There’s a fence put up around the building because the structure is unstable, but it’s still interesting to walk around the outside and wonder what went on when people still inhabited it.