This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

A solar-powered primary school inspires hope and experimentation in a country ripe for energy innovation.

Space-age monument to an early 20th-century uprising.

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

An homage to the medieval rulers of Bulgaria.

Sofia's legislative center is continuously reinventing itself.

This massive stone and steel monument remembers a century-old battle that cost thousands of lives and nearly destroyed the city.

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

A vast Communist-era exhibition space in the Bulgarian capital.

"Unity, Creativity, Beauty."

Eastern Bloc nostalgia, anybody?

This once-grandiose behemoth of a monument from the socialist era now sits quiet and closed up.

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

A collection of art from Bulgaria's time as a communist state.

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

This massive concrete sculpture is said to be the heaviest communist monument on Earth.

An abandoned saucer-shaped monument in the Bulgarian mountains.

The birthplace of a titan of American cinema.

One of Frank Lloyd Wright's final works was this UFO church.

A unique botanical garden housed in three giant geodesic domes.

The bugs crawling down the front of this office building are almost as big as a '68 VW Beetle.

An off-the-beaten-path place to literally hang beneath Milwaukee's Holton Street Bridge.

The unluckiest U-boat in the entire German fleet is now on display in a Chicago museum.

This bronze sculpture on a former squash court marks the secret origins of the Atomic Age.