This building holds the embalmed remains of the leader of the Bolshevik Revolution.

An underground city of salt.

Two very green residential towers cleaning the air in one of Europe's most polluted cities.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

Gargoyle head that brings good luck.

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

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

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

This Polish cave has housed a dragon, a brothel, and an enduring legend.

Erotic art covers the walls of the largest ancient pleasure palace.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

Ancient snack bar of the Roman Empire re-opened.

Macabre astrological automaton clock dating to the late 1400s.