The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

This balancing rock is one of Utah's most unusual geological formations.

A solid steel plane designed to catch fire over and over again.

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

Where royalty waits in the height of luxury.

Some 80,000 Delft Blue tiles line the inside of this Amsterdam walkway.

A Dutch passageway's artistic, aquatic-themed makeover pays tribute to the capital city's famed waterways.

This city square is home to Amsterdam's oldest church and a statue honoring Dutch sex workers.

One of Amsterdam's narrowest houses is located right across the canal from its widest.

Amsterdam's former hotspot for public executions and dissections.

The former headquarters of history's oldest megacorporation.

A public urinal so pretty, it was declared a national monument.

The facade of this bank has changed little over the centuries, including its unique welcome sign.

In the days before house numbers, these colorful signs held clues about various buildings' purposes.

Europe's official "zero-level," the equator of elevation.

Three connected pink triangles memorialize persecuted gays and lesbians throughout history.

This impressive collection of rare books on ancient mysticism inspired author Dan Brown.

A floating cat sanctuary on an Amsterdam canal.

Amsterdam's narrowest house facade is a monument to 17th-century tax evasion.

This old KLM airplane cut into three parts was transformed into an eclectic airport gift shop.

The first Confucian temple in Taiwan, founded by the son of a pirate lord, doubled as the island's first state-sponsored school.

A UFO-shaped event building originally intended to be a science museum showcasing the future.

A Black Forest cuckoo clock theme park features one timepiece big enough to walk inside.

This memorial commemorating fallen Swiss Guards of the French Revolution has been called the saddest stone in the world.