On either side of a gorge high in the Peruvian Andes, an aging rope bridge sags precariously over the Apurímac River. 1 of 13 A Quechua man walks across the old suspension bridge at the start of ...

The much anticipated rope bridge spans the Clinton River, giving parkgoers access to the 48-acre Innovation Hills Green Space, which is the city’s largest and highest quality green space.

The bridge on the National Mall will be made of hundreds of ropes of varying thicknesses. The math involved is formidable. “It’s like calculus,” Valencia says.