Abandoned railway line circling the city of Paris.

Two awe-inspiring globes from the reign of the Sun King hang from the ceiling of France's national library.

Housing the groundbreaking maps and globes of Gerard Mercator.

This miniature take on the Kremlin is one Dutch man's retirement project.

Below a historic English market town lies a secret underground city complete with kitchens, laundries, storerooms, and an underground lake.

1513 Turkish world map, full of European state secrets and snarky commentary.

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

A marvel of Byzantine engineering under the streets of Istanbul.

This historic black and white monastery is one of Bulgaria's architectural jewels.

Stone pillars and a petrified wedding party in the hills of North Macedonia.

Bizarrely shaped rock formations in northwest Bulgaria come with equally bizarre legends.

The ceiling of Prohodna Cave in northern Bulgaria affords a peek at the sky via two deity-sized-eye-shaped holes.

A flamboyant five-story building in Bulgaria resembles a crawling snail.

Eastern Bloc nostalgia, anybody?

A Bulgarian monument to Russia's role in World War II is constantly being painted in pop culture protest.