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

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.

A Trabant car, a kangaroo statue, and a plethora of plants take over this abandoned-factory-turned-bar.

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.

Freddie Mercury's childhood home is now a monument to the iconic Queen rockstar.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

Abstract dinosaur models in London.

The curios of pharmacist and collector Henry Wellcome.

A hands-off space for graffiti artists to hone and display their skills.

A museum wholly devoted to juvenescence.

This South London cemetery holds the remains of more than 15,000 people.

A little slice of Japan and its aesthetics in London's Holland Park.

This artist's home turned gallery/museum preserves the creator's love of "Eastern" influences.

One of the world's tallest statues is also one of its most hated.

Gargantuan home of Russian science.

The gorgeous entrances into the city's underbelly look more like grand halls than subway stops.

This mystical orb covered in strange symbols is thought to have been used in ancient Greek magical rituals.

This small 16th-century church in Athens is almost entirely surrounded by a modern building.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

150 or so scrounged-up lamps, chandeliers, and lanterns light up this alley in central Athens.

The only surviving choragic monument is a trophy awarded in 334 BC for the winning dramatic chorus.