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

Gargoyle head that brings good luck.

A stunning mosque owes its design to an Ottoman ruler nicknamed "the Butcher."

The only quarter of the Old City not dedicated to a major world religion.

An ancient underground cultic temple where sunlight penetrates on the summer solstice.

The tallest waterfall in the Judean Desert is named for its connection to a biblical figure.

This daunting 1st century fortress was purportedly the site of one of the most dramatic revolts of the Jewish-Roman wars.

The bluer than blue waters in these natural Israeli caves are reached via the world's steepest cable car.

A towering spire in the fortress of Kalemegdan honors the victorious armies of Serbia during their struggles against the Ottoman Empire.

A museum dedicated to the former country.

A misnamed well, with a deep dark past.

Destroyed Serbian army headquarters sits half crumbled in a largely revitalized Belgrade.

Nikola Tesla's ashes are held in a golden sphere, surrounded by his works.

A Red Cross memorial museum at the site of the Niš concentration camp that operated for four eventful years during World War II.

This memorial park stands on the site of one of the largest mass executions of the Second World War.

Structure built from the skulls of vanquished foes.

Underground monastery and fortress.

A museum glorifying the life of Stalin, located in the city of his birth.

An collection of Chinese propaganda posters from 1949 to 1979.

France's most famous cemetery, with some of its most curious tombs.

A memorial to those who died at the hands of the Kuomintang while fighting for communism in China.

A prestigious learning institute of old Shanghai.

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

An ancient fortification lives on in this Chinese city.