One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

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

This little medieval church hidden in the center of Yerevan was lost and rediscovered—twice.

This medieval manuscript collection has some of the most obscure and ancient texts in the world.

At this rare mosque in Tbilisi, Sunni and Shia Muslims pray side by side.

You'll find just about anything in this funky Tbilisi flea market.

A cluster of historic bathhouses built on the famed hot springs that gave the Georgian capital its name.

A small but hugely whimsical theater where marionettes play out the "The Battle of Stalingrad."

The charmingly disheveled clock tower of Tbilisi's puppet theater.

Elaborate series of tunnels where traces of mass suicide are still visible.

The largest bell in the world has been swinging high above a Cologne cathedral for almost a century.

Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.

Take a walk in a recreation of ancient Rome.

Twisted buildings adorn the banks of the Rhine river.

These tenacious 14th-century towers defied demolition and are now a fairytale vacation rental.

This futuristic German television spire is actually the world's largest digital clock.

This "floating railway" is one of the world's oldest monorail systems.