A collection of abandoned typographic signs from Berlin and beyond.

This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.

This one-of-a-kind Roman arch is not actually dedicated to the god Janus.

This remnant of an ancient Persian city is considered to be the world's largest single-span brick vault arch.

A natural arch carved by a river gave its name to the so-called "Cave of Forgotten Dreams."

This magical-looking island is notorious for the misfortunes suffered by its owners.

The second-largest natural arch in the Chartreuse Mountains.

The "Black Arch" guards the entrance to the picturesque Glens of Antrim.

A strenuous, unofficial trail leads to spectacular views in one of America's most remote national monuments.

Unscathed for almost 2,000 years, the best preserved Roman triumphal arch is in a small southern Italian city.

The fifth-longest natural arch in the world, and the longest outside China.

Unlike most arches, this geological oddity formed in a volcanic dike.

This striking arch, one of the first architectural elements constructed in Prospect Park, was recently restored to its original glory.

This clifftop arch is a natural stunner.

This magnificent arch is all that remains of a former smelt mill.

This bird-shaped rock formation defies gravity, time, and classification.

It's safe—and permitted—to walk across these twin natural sandstone arches.

The Yiddish language stages a renaissance in a shtetl-inspired cultural center on the San Diego coast.

One of the best collections of antique printing machinery in the world.

This bridge was constructed from the rubble of the infamous Bastille.

A favorite Paris bar for U.S. expats, including Gershwin, Hemingway, and James Bond.

A simple plaque on the facade is the only reminder that the treaty ending the American Revolution was signed inside.

This small, ingenious cannon once helped regulate Parisian life.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.