Thousands of flowers create enchanting pink tunnels over the city streets.

This bazaar is one of the oldest in the Arabian world.

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

The avant-garde design was able to bypass strict Soviet regulations on architecture.

An early-20th-century "dacha" village of quaint cottages curiously located in a modern part of Moscow.

Back in the tiny USSR.

Former headquarters of the KGB.

Moscow's other, lesser known kremlin is a fairytale-like cultural complex modeled after Old Russia.

The studio of Catalonia's most famous theatrical designer remains exactly as he left it.

The remains of the last Bosnian fortress to fall to the Ottomans are still standing.

A number of craters left by fatal mortar strikes have been filled with red resin to remember those lost during the Siege of Sarajevo.

Bridge that died in war and was resurected.

This museum preserves the hand-dug tunnel that kept Sarajevo afloat during the Serbian siege.

Oriental bazaar in the heart of Sarajevo.

This historic cemetery was inaccessible for several years due to dozens of land mines.

The remains of a sunken military ship wreck visible through clear water.

Large, airy hallways hide within an impenetrable fortress that beckons urban explorers.

The Victorian-era greenhouse is stuffed with tropical plants, and open 365 days a year.

A bizarre house filled with an astounding array of collections.

Longest fortress system anywhere in Europe.

This surreal memorial/cemetery is a necropolis of crumbling stonework and puzzle-shaped headstones.

Formerly Yugoslavia's "forbidden island," this sleepy little city still holds the abandoned remains of military strongholds.

A growing popular hipster market with over 100 local specialties and live music.

A unique Holocaust memorial tells the personal stories of the Jewish residents exiled from greater Berlin.