The last remnants of a massive medieval wall that once encompassed the city of Berlin.

Tiny memorials honor individual victims of the Holocaust.

This water-tower-turned-high-end-apartment building was once the site of an early Nazi concentration camp.

Once a path for Jewish funeral processions, this unassuming alleyway is rich in local lore.

What started as a tongue-in-cheek shrine is now a full-blown museum celebrating "The Hoff" and his longtime love affair with Berlin.

Inside this Jewish cemetery is a memorial to soldiers who deserted the German army and were executed.

These former Nazi anti-aircraft towers offer a singular view of the north of Berlin in the summer, and a sanctuary for bats in winter.

Known simply as "The Hand," this famous public sculpture in Berlin was featured in a Depeche Mode music video.

Someone loved this song enough to carve all of its lyrics onto a tree trunk in a Berlin park.

This obscene artwork on the side of a newspaper office pokes fun at a rival paper's former editor-in-chief.

Most-visited and most-photographed slot canyon in the American Southwest.

The location where the iconic movie character declared it was time to go home.

An abandoned Byzantine fortress and notorious prison.

One of the most photographed locations in the entire city.

Monasteries on rock pillars, once accessible only by frayed ropes.

A striking symbol of the Bulgarian capital.

Eastern Bloc nostalgia, anybody?

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

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

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

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

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

Ruins of a German castle on top of a towering stone pillar.

A preserved college lock-up that recalls a clubhouse approach to discipline.