The ruins of a medieval monastery built on a perilous slope.

A geological oddity topped with a 2,000-year-old pagan temple.

Rock-hewn monastery complex with hundreds of cave structures tucked away into the mountainside.

This Armenian monastery was carved out of cliffs and named after the spear used to stab Jesus.

This ancient monastery complex was transformed from an island to a peninsula when the lake was partially drained.

It took 160 years to complete the most ornate church in Ecuador.

Three hundred years of preserved Spanish colonial history in San Antonio.

This mysterious but iconic tapered tower appears in many Azeri fairytales and legends.

A shrine of fire worship built on top of a natural flame.

Supposedly this Ethiopian chapel holds the Ark of the Covenant, guarded by virgins who cannot leave the building.

Reaching the "Church in the Sky" requires scaling the cliff face of a sandstone pinnacle with a 650-foot drop.

An Ethiopian "Jerusalem" featuring a church hewn out of a single rock.

The cathedral stands in New Jufa, Isfahan's Armenian quarter that was established in 1606.

A set of ancient drawings in the desert of Peru that are so massive, many of them can only be fully seen from the sky.

A spiritual vortex among the red rocks in Sedona.

The ancient necropolis houses the immense rock-cut tombs of four Persian kings.

A Zoroastrian funerary tower where excarnation rituals are carried out is threatened by the area's dwindling vulture population.

This representation of Lord Vishnu is the largest stone sculpture in Nepal.

Massive series of 45 caves and over 51,000 sculptures carved from cliffsides in China.

This sacred fig tree with a link to the Buddha is one of the oldest human-planted trees in the world.

Although resembling a grand Buddhist temple, this structure is actually the largest mosque in China.

This amazing mountain temple is topped by one of the tallest sitting Buddha statues in the world.

This Buddhist monastery once housed an image of Buddha containing a 19-carat diamond.

A 14th-century European chapel sticks out of the facade of a Japanese hotel.