A marvel of Byzantine engineering under the streets of Istanbul.

A peculiarly shaped brass sculpture hidden in a courtyard in central Lviv

Padlocks cover this rickety footbridge with love.

Remains of a station that only operated for one year.

An Art Nouveau building covered in animal gargoyles and grotesques.

In the land of the Light Brigade stands a testament to the Cold War.

A former steam-powered mill from the 1800s is now an industrial park with a giant steel dragon slide.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

Uh, pardon me, ma'am, but I couldn't help noticing that there's a Columbo statue in the middle of Budapest.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

Once the home of a hermetic monk, this cave now houses a small church.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.