A 20th-century picture show in 3-D.

Order “Proletariat’s Cutlet” at this communist-themed restaurant allegedly once visited by Lenin.

A statue honors the children who fought Nazis in Poland.

A hidden art gallery in an abandoned Warsaw fort.

Warsaw's fantastically preserved gasworks...almost.

After the famous composer died in Paris, his sister snuck his heart out of the country to honor his wish that it be buried in their native country.

A program of Communist glamour in post-Stalin Poland is preserved in this colorful museum.

A gorgeous, Gaudí-esque stairway constructed in the city of Istanbul by a prominent Jewish family.

The legendary luxury train passage is commemorated with a charming museum inside its former eastern terminus.

A sixth-century Byzantine cistern hidden below a modern carpet store.

A marvel of Byzantine engineering under the streets of Istanbul.

A surprising and unconventional mosque hidden in the subsoil of Istanbul.

The home-turned-museum of Barış Manço, the mustachioed Turkish Elvis for children.

A tiny park in the middle of some big power politics.

It's believed that this small church was connected to the Hagia Sophia via a secret tunnel.

A small etching on the white marble parapet was written in runic script by a Viking mercenary.

A meow-velous tribute to a beloved street cat, made famous on the internet.

This remarkably well-preserved Egyptian plinth is pretty well traveled for a giant piece of stone.

Turkish adventurer antiques in the heart of the Grand Bazaar.

Colorful power station with a chimney equipped with a gallery for exhaust monitoring equipment.

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

There was a top secret plan during World War II to seal a group of soldiers inside the rock.

Single runway interrupted by a busy road that cuts across its middle.

An eccentric collection of antique items shares space with a prop-quality witchcraft museum.