This "floating railway" is one of the world's oldest monorail systems.

Sofia's legislative center is continuously reinventing itself.

"Holy Wisdom" overlooks the city that became its namesake.

A striking symbol of the Bulgarian capital.

A pair of connected skyscrapers form this symbolic gateway.

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

An ancient Egyptian temple in the middle of Madrid, Spain.

This underground church is topped with a 500-foot cross that is seen by many as a beacon of fascist hubris.

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

A spectacular Bulgarian cave resembling a devil's head with a waterfall rushing down its throat.

This ancient theater, restored in the 20th century, lives on as a venue for dramatic and musical performances.