One of few vertical lava tubes in the world accessible by foot.

Perhaps the most spectacular grotto along the Algarve coastline.

These gigantic skeletons tower over visitors and provide insight into the creatures that once ruled over Ireland.

Amidst the bustling streets of Dublin, there is a hushed garden that is dedicated to "All those who gave their lives in the cause of Irish Freedom."

The house where the writer spent his formative years.

The comedy and tragedy of Oscar Wilde is preserved in a Dublin park, captured in a sculpture of colorful stone.

This permanent collection of preserved bodies taken from Irish bogs is one of the leading authorities on such morbid mummies.

Dublin's "Dead Zoo" serves as a window to Victorian museum design.

Touching this 18th-century Scottish philosopher’s toe allegedly conjures good fortune.

The most loyal of little dogs, or a Victorian era publicity stunt?

Overlooked by many, the two famous Scottish warriors guard the main gate of Edinburgh Castle.

The highest peak in the United Kingdom has a history of physics, specters, and a pilgrimage of strange objects.

There are plenty of wonderful panoramic vistas in Edinburgh, but not many are hidden smack in the middle of the Old Town.

This portion of a lovely Belize beach is infested with (harmless) sharks and rays.

A museum dedicated to one of Paris’s most famous residents, tucked into a corner of one of the city’s most famous squares.

The first green space constructed on an elevated viaduct.

Sip cherry liqueur at a bar dating back to 1840.

Eat the ultimate iteration of Portugal's most beloved pastry.

This small city park is best known for the nightly convergence of thousands of shrieking parakeets.

The world's tallest palm trees look like the whimsical kind of plant you'd find in a Dr. Seuss story.

One of Mexico's least-visited archaeological sites is tucked away inside a theme park.

This church was transported brick by brick from the ruins of a 16th-century city into Panama City's current historic district.

These pastel-colored homes were built when the island of Macau was a Portuguese colony.

This massive boulder was hurled into a Zurich church when a gunpowder depot was struck by lightning in 1652.