This ornate church has survived Nazi and Soviet occupation, including a short stint as a Soviet-era gymnasium and cinema.

An abandoned masterpiece of Soviet Brutalist architecture.

This striking structure is the Socialist-modernist centerpiece of a former Soviet spa resort.

This striking memorial is one of Estonia’s most controversial Soviet leftovers.

A statue of the Soviet leader still stands in a quiet corner of Estonia’s most Russian city.

A series of concentric circles represented a bold new experiment in socialist urban planning, and it notoriously difficult to get around.

A tower marking the spot where Yugoslavia began its resistance against the invading Nazis stands neglected, but not quite forgotten.

A forgotten and crumbling Yugoslav monument to the victims of fascism.

Abstract monuments express sorrow and resilience at the site of a horrific massacre in Nazi-occupied Serbia.

Curious carved stones and bird-like wings are a symbol of Serbian resilience and freedom on the site of a WWII massacre.

An abandoned monument remembering the "Pančevo Holocaust" now stands as a shadow of its former self.

This symbol of Yugoslav liberation decorated with 620 carved heads of mythical creatures is now a forlorn relic of another time.

A grand Yugoslav memorial to the group of partisans who fought and died resisting western Serbia’s Nazi occupation.

Built as an anti-fascist tribute, this surreal Yugoslav memorial became an unwelcome symbol after the Croatian war for independence.

A subterranean ice warehouse that has lain hidden beneath central London for over a century is now open to the public.

A forgotten remnant of the Soviet Union, Transnistria is an unrecognized country hidden behind a heavily militarized border between Moldova and Ukraine.

The industrial monstrosity known as Bagger 258 is a colossal mining machine built in the DDR - but now left for dead in a German field.

A unique collection of Soviet military artifacts lies hidden away in a disused train, in the unrecognized Eastern European republic of Transnistria.

A cave network located at the southernmost tip of mainland Greece was once believed to be an entrance to Hades.

Hellam Township is reputed to feature seven remote gates, which when passed through in the right order, open an entrance to hell.

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

According to one local tradition, the entrance to the Voodoo underworld can be found in New Orleans through seven gates scattered throughout the city's French Quarter.

A stratovolcano located in the south of Iceland, with a long history of charted activity and a rich mythology attached.

A macabre sculpture museum in the capital of Haiti fuses human bones with broken metal to create challenging contemporary art.