The Cycladic architecture makes this Athens neighborhood feel like an island paradise hidden in the shadow of the Acropolis.

This graffitied 19th-century building was a prototype of European industrial architecture.

One of the most photographed locations in the entire city.

A little-known park with unusual, half-ruined structures and a mystical energy.

Thousands of rusting train cars have been slowly falling apart on the edge of Greece's second largest city.

This concrete residential area doubles as an open-air gallery.

Keep your eyes out for this "ghost" and walking pun.

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

A collection of abandoned typographic signs from Berlin and beyond.

Metro station with a claim to rock n' roll fame.

An imperial church bombed to ruins during WWII now stands as a jagged memorial.

This little museum is making sure that the art and history of the graffiti sticker is not scraped from history.

This monumental work of art symbolizes the coming together of a previously divided city.

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

A monument to the man who almost killed Hitler.

The site where a plot to assassinate Hitler was planned—and its conspirators were executed—is now a powerful memorial to the German resistance during World War II.

The world's first clock to use set theory as a measure of time required the invention of a new light bulb just to maintain its obtuse measurements.

An astonishingly accurate water clock that doubles as an hourly spectacle in this Berlin shopping area.

A little sculpture with a large wardrobe.

Meet the bronze beloved pet to a family of famous peeing statues.

Brussels' favorite peeing boy has a sister.

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.

An abandoned NSA listening post on Berlin's "Devil's Mountain."

A memorial in the Tiergarten is a reminder of the suffering inflicted on homosexuals by the Nazi regime.