Cuyperspassage

This unassuming tunnel’s name recalls a storied "cat pond" that has now been lost.

An abstract sculpture that will be a work in progress for the next 1,000 years.

A working-class suburb has become an open-air art museum dedicated to a local poet and hero of the Spanish Civil War.

An unconventional monument to one of America's largest landowners.

This colossal underground passage paved the way for large-scale drainage and access tunnels across the U.S., but it almost wasn’t built.

An art installation commemorates journalist Nellie Bly's undercover reporting inside a New York asylum.

Three historic trains run on a half-mile track that features a tunnel.

Located more than 600 feet beneath sea level, this tunnel boasts the world's first undersea roundabout.