This blowhole is supposedly caused by a trapped monster.

This former luxury resort in Kaua'i is now an abandoned relic.

A prehistoric landscape hidden in the cliffs of Maha'ulepu.

A Hawaiian stairway to heaven—that you can't climb.

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

The history and future of cannabis.

The quaint little store that is said to have inspired a famous Dickens novel was only given its name after the book was released.

Hear the quietest sound from across the dome.

Public access to clean drinking water was an instant hit among the masses.

This little-known relic crypt holds stolen parts of a Roman Empress.

The celebrated eyesore created by starry-eyed sweethearts.

A remarkably intact castle that once was the largest in Ireland.

While only two of the ancient buildings at this site are actually churches this was one of the earliest Irish pilgrimage sites ever.

The modern birthplace of Irish freedom.

The somber sculptures commemorating Irish Famine on the river Liffey in Dublin.

Medicinal spa created with the discharge from a geothermal energy plant.

A "simple-hearted artist" turned an isolated Icelandic valley into his own art museum.

A formerly glacier-tipped volcano that inspired none other than Jules Verne.

The picturesque birthplace of Icelandic democracy is drenched in the blood of its brutal past.

Twisted girders are all that remain of an Icelandic bridge that was wiped out by a combination of volcanic heat and glacial floods.

This eye-popping Icelandic crater lake is surrounded by red volcanic rock.

This fantastical waterfall is hidden in a cave located in a cracked cliff.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

This scenic Icelandic lava flow is named for a pair of Berserkers who were murdered, according to a famous Saga.