Medieval ruins nestled within a breathtaking swath of Spanish nature.

A dreamlike medieval church dug into the tuff rock, with unusual carvings and possible traces of the Templar knights.

A historic Christian shrine nestled within a spectacular natural cave.

These ruins of Francis Bacon's once-magnificent manor are hidden in the English countryside.

A 19th-century funicular railway shuttles visitors up this surprising sea cliff to one of the world's largest camera obscuras.

The marshy karst plain has reclaimed this beautiful 17th-century church.

Modern megaliths form this work of cosmic, Celtic landscape art.

This 50-foot-deep sinkhole created in the 14th century is home to rare plants and fungi.

This secluded walkway overlooks a magnificently wild London green space.

A magnificent Neogothic tomb hides within this Italian fairytale-like forest.

More than a million titles fill the labyrinthine shelves of this prestigious private library.

You can crawl inside this atmospheric 5,000-year-old tomb.

This hilltop ruin is of the hundreds of stone columns built in tribute to the first German chancellor.

An ancient pagan site swirling with legends in the foothills of Franconian Switzerland.

Rows of multicolored bathing huts paint the sand dunes with pops of color.

This old Victorian bathhouse is fed by an ancient spring.

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

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

Trek into the depths of the cave where 17,000-year-old paintings exist alongside 400-year-old graffiti.

This cathedral hides a sculpted dog that determines your fate and an unexploded shell from World War II.

The second-highest village in Lazio has attracted artists for 400 years and is now a spectacular open-air art gallery.

This garden houses the remains of the ancient Greek port of Marseille.

Unusual books about food and drink abound in this 19th-century New York townhouse.

The city of Palestrina was built around this magnificent terraced sanctuary dedicated to the pagan goddess Fortuna.