Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

This semi-secret storybook hedge maze is also the oldest garden in the city.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

The stunningly blue waters of these beautiful caves also have a violent past.

After being destroyed by IRA sympathizers, the ruins of this stately Irish manor have sat vacant for decades.

The ancient tomb acts as a calendar that keeps perfect time.

An ancient neolithic tomb that only sees the sun twice a year.

This 5,300-year-old tomb with mysterious carvings crowns an Irish mountain.

A corkscrew-shaped barn in Ireland.

There might not be much left of these Irish ruins, but their linguistic legacy is still going strong.

This Bronze Age tomb is the centerpiece of a clearing within a beautiful Irish forest.

This pub built its reputation pouring post-shift pints for employees of the cemetery with which it shares a wall.

This is the largest cemetery in Ireland and the first cemetery museum in the world.

The burial place of 14 of the executed leaders of the Easter Rising.

An existential riddle in the world's largest ancient castle.

The former home of Dutch anthropologist Bert Flint now houses a collection of Berber art and artifacts.

"There's nothing there," and other lies the KGB told us.

The Guardian of Tallinn.

Only a fragment of this 15th-century Dance of Death survives today.

This medieval Estonian tower provides access to a series of tunnels that have been home to soldiers, punks, and fine art.

Islanders once used this dramatic, otherworldly landscape to hide their cattle from Viking raiders.

On this stunning Scottish island, you can walk in the footsteps of dinosaurs.

These fantastically named natural pools look like something out of a Scottish myth.