Europe's largest prehistoric mound – burial site of a legendary king?

The largest stone circle in the world has ended up bringing up more questions than it has answered.

A decaying, yet still functioning, work of communist architecture.

An homage to the medieval rulers of Bulgaria.

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

Sofia's legislative center is continuously reinventing itself.

A striking symbol of the Bulgarian capital.

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

This building has two facades of clashing architectural designs.

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

Outstanding, eerie frescoes and decorations fill this 19th-century monastery.

Rebuilt several decades ago, its striking murals prevent it from being reconsecrated as a church.

Said to be the only museum in the world dedicated to the most classic of all blooms, the rose.

A magnificent, glittering building tucked into a tiny Bulgarian mountain town.

A mountain pass in Bulgaria's Balkan Mountains was the site of four historic battles.

An abandoned saucer-shaped monument in the Bulgarian mountains.

A gigantic statue of a Russian soldier watches over the ancient city of Plovdiv, a prominent reminder of the Soviet period in Bulgaria.

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

A 18th century graveyard and its astonishing cortege of macabre iconography.

This mundane post marks the old location of the city's main postal hub.

A roadway designed for a visiting monarch.

This obscure walkway links Edinburgh’s Old Town with one of the city's prime vantage points.

Neon artworks light up this dark Edinburgh tunnel.

Poetic, metallic giraffes adorn a square off an Edinburgh thoroughfare.