A floating underwater hotel, created by a Swedish artist.

This historic hotel preserves many treasures from its heyday hosting passengers on the Orient Express.

Remnants of successive wars and Muslim colonialism in the 11th century.

A beautiful 19th-century Armenian mansion is preserved above an unassuming cafe.

This hidden gem is bathed in beautiful natural light.

An ancient church on a tiny island covered in stone bible stories has controversially been turned into a museum.

Standing proud atop a Turkish bluff, this Ottoman palace has retained its grandeur despite being abandoned for centuries.

An abused and forgotten metropolis, abandoned for centuries.

Home to a collection of drums from around the world that allow visitors to play a tune.

This monument celebrates this shopping district's past history as a feudal silver mint.

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

While not Turkey's deepest underground city, this subterranean redoubt is the largest.

Five sultans and their families rest in eternal splendor, teeming with overlooked beauty and drama.

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