The swooping roof of the David L. Lawrence Convention Center in Pittsburgh hangs from a series of 15 enormous cables tied to tall masts.
Designed by architect Rafael Viñoly, the structure mimics the curves of Pittsburgh's many suspension bridges.
The cable-suspended roof owes its graceful shape to the natural curve formed by a flexible cable or chain hanging between its fixed ends—a catenary.
The cables end in exposed anchors (above) inside and on the roof, visible to passersby.
Photos by I. Peterson