This rare example of a "tidefall" is a spectacular drop from the cliffs down onto the beach.

A mesmerizing reservoir nestled at the heart of a pre-Islamic Yemeni village.

This mesmerizingly colorful pond looks like a scene straight out of a fairytale.

This 13th-century monastery chiseled into the side of a mountain is equipped with a bridge that can be lifted to protect against raids.

Perhaps the most spectacular grotto along the Algarve coastline.

The eerie remnants of an ancient forest were hidden under the sand for centuries.

This outcropping was once home to a medieval monastery destroyed during the Ottoman conquest.

An ancient Scottish rock formation said to be the gravesite of a giant remains ensconced in legend and intrigue.

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

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

This ancient altar emerges from the thick forests to reveal the mysteries of Etruscan sacrificial rituals.

Italian director Pier Paolo Pasolini fell in love with this lonely 13th-century tower while making his most famous film.

A fascinating assortment of cave dwellings, medieval ruins, and sarcophagi are being devoured by the forest.

Ancient, mysterious stone altars are hidden among wild woods in central Italy.

A 16th-century horror show built in a lovely Italian garden.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

A medieval bridge stretches over a sulfur-rich river that leads to year-round natural hot springs.

Romans built the world's tallest artificial waterfall in 271 BC.

This medieval mountain town is also known as the "Village of Streams."

On the Oregon coast there is a natural hole that seems to be draining the sea.