Two small chapels housed inside an ancient tree.

A village on the east coast of England that has almost completely eroded into the North Sea.

A dangling church built over a Colombian gorge.

This underground church is topped with a 500-foot cross that is seen by many as a beacon of fascist hubris.

Hundreds of stone stairs and a winding medieval bridge connect this haunting Spanish island to the mainland.

This medieval church tower has maintained its clockworks since the 16th century.

Historic church where a number of Shakespeare's actors are buried.

A historic house devoted to the teachings of a 1700's prophetess and her mysterious box of revelations.

Human-made caves excavated to hide a secret society of wealthy pagans.

This small chapel is built of human bones and decorated with a golden skeleton.

One of the oldest libraries in England, and one of the last of the great medieval chained collections.

Oxford University's stateliest library seems designed to make students truly feel the weight of knowledge.

A chunk of the "true cross" is held in this small Portuguese church where modern day exorcisms are said to be common place.

Houses are tucked between, on, and underneath giant boulders.

Below a historic English market town lies a secret underground city complete with kitchens, laundries, storerooms, and an underground lake.

This 15th century pub is one of only two pubs in England situated on consecrated ground.

Cathedral carved out of salt, located a mile below the earth's surface.

This oddly shaped church resembles a rocket.

Detailed sandstone carvings show an array of symbolism and adorable animals.

The corpse bride of Portugal.

Decaying 18th-century church converted to a single-family home.

This hospital once pioneered the use of electroencephalograms, but fell into maltreatment, abuse, and eventual abandonment.

Ancient catacombs form the foundation for this Rococo orgy of a church.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.