A mechanized clock where a man fights off a dragon, crab, and rooster.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

What looks like a normal building is really a hollow facade hiding a subway vent.

Down a cobblestone alleyway is a museum dedicated to Romanticism, with a secret garden.

It appears as if a man is standing behind this giant airport clock, painting the hands in real time.

Iceland's tribute to its thankless civil servants.

These barriers stand as stark reminders of Northern Ireland's troubled past.

A towering monument to war, located on a beautifully peaceful hill.

Rich with fauna and flora, nature-lovers can walk across the sea at this UNESCO World Heritage spot.

The Swedish flag over this small naval fort signals that the nation is at peace.

This public library and its impressive collection of academic books have not changed since the 17th century.

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

Latvia's symbolic mountain-shaped national library is home to millions of cultural tomes.

It was once nicknamed "the most bombed hotel in Europe."

A palatial former bank building now houses what may be the poshest art venue (and former Tesco) in Belfast.

The Netherlands' first car tunnel has an unusually rectangular shape.

A hidden three-foot-wide house separates these two regal churches.

Most of Britain's gold reserve was secretly stashed here after the start of World War II.

Inside this Icelandic greenhouse, geothermal energy keeps tomatoes warm and growing.

Eighty million natural history specimens call this gargantuan museum home.

Sofia's legislative center is continuously reinventing itself.

A vast Communist-era exhibition space in the Bulgarian capital.

"Holy Wisdom" overlooks the city that became its namesake.

A striking symbol of the Bulgarian capital.