New York City’s skyline features a myriad of water towers, but one in particular stands out from the rest. MoMA’s rooftop sculpture garden features the familiar steel frame, but the container appears to be missing. In its place, you’ll find what looks like water in the shape of a coned cylinder resting atop the structure.

The 12-foot-tall resin cast of the inside of a water tower is English artist Rachel Whiteread’s first public sculpture to be conceived and displayed in the U.S. After she was commissioned by the Public Art Fund in the ‘90s, she searched the city for what she felt would be a quintessential New York City symbol.

Whiteread is known for her castings of everyday objects like bathtubs, hot water bottles, and even an entire Victorian house. “Water Tower” was made using a once-functioning cedar tower. She chose it for the wood’s distinct texture, which she then imprinted on the casting. The translucent sculpture changes color and brightness with the weather and is all but invisible at night.

The piece was installed on a rooftop on West Broadway and Grand Street in SoHo in 1998, but it has since been moved to MoMA. Like Whiteread’s other works, it almost appears to be a fossil. If you’re ever at MoMA, keep an eye out for the glowing artifact of city life.