This tiny island featuring 9th-century Viking ruins is only accessible at low tide.

Amazing and mysterious Neolithic settlement on Scotland's Orkney Islands.

Vienna's diversity-themed traffic lights were inspired by the Eurovision Song Contest.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

Giant WWII fortresses that fired 8,000 rounds a minute, now home to thousands of pigeons.

An exquisite Baroque church in Vienna's old town.

Legends surround an ancient tree trunk riddled with nails for good luck.

Baroque celebration of the end of the Great Plague of Vienna.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

A tropical paradise just a short trip from the opera house is filled with beautiful winged creatures.

The beautiful baroque library of the Hapsburg empire.

This inn of the court provides a fascinating window into London’s legal and architectural history.

Built by George III to observe the transit of Venus, this Georgian gem is a unique survivor in the Arcadian landscape of Richmond upon Thames.

Chelsea's soldiers were given strict orders when crossing this historic bridge.

A haunting painting meant to capture the calamity of World War I.

This once-controversial and slightly confusing statue of Achilles was built out of captured cannons.

The Great Fire of London and the regulation of one-way streets both started in this alley.

This Underground station has been a popular filming location for decades, even before it closed.

A series of carved figures that scandalized British society.

A gallery specifically dedicated to the botanical illustrations of a remarkable traveling lady.

A mysterious shape catches the eye in this 16th-century painting.

These wire animal sculptures commemorate the exotic inhabitants that once called the Tower of London home.

This ancient Egyptian obelisk still bears the wounds of World War I.

Putting the "mod" in "modular" since 2000.