A former imperial sea-fortress and Soviet prison.

Estonia's largest creative city is a vibrant bohemian hub located within a former industrial complex.

A symbol for the opposition to nuclear power around the world.

This colorful artistic feature atop a Danish art gallery allows visitors to stroll through a rainbow.

Denmark’s never-ending bridge.

A copy of the Statue of Liberty greets visitors to the birthplace of Auguste Bartholdi.

A colossal sculptural lion built by the same man who designed the Statue of Liberty.

This statue pays tribute to the iconic musician in the place where he recorded his final studio album.

A permanent exhibition honors Queen, which recorded seven albums at the casino-based studio, including “Under Pressure” with David Bowie.

This fountain is dedicated to the workers who perished constructing the Fréjus Rail Tunnel.

This fishing contraption sits on top of a series of spindly wooden stilts.

This small but lovely sinkhole lake is the last remnant of a great prehistoric water basin.

A small thermal park among the mountains of Southern Italy features a surprising piece of modern art.

A cave in southern Italy adorned with thousand-year-old Biblical frescoes existed in obscurity until fairly recently.

Skulls and skeletons are omnipresent in this church dedicated to souls trapped in purgatory.

An abandoned quarry hides an open-air gallery of huge sculptures, some made from the rubble of 9/11.

Legend says this sacred tree was a gift from goddess Athena.

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

The world's most active stratovolcano is almost always erupting.

This triumphal 16th-century arched gateway leads to the oldest street in Palermo.

This mosaic-lined medieval church was built by the world's first admiral and still holds mass in ancient Greek.

Haunting graffiti left by prisoners of the Spanish Inquisition.

This skeletal, unfinished Gothic church once housed a miraculous masterpiece by Raphael.

A narrow opening between the mountains of the Amalfi Coast creates a scenic hidden beach.