In downtown Oslo, a menacing and terrifying relief clings to a church wall.

Famous for his giant trolls, Thomas Dambo's lesser-known early work is a creative 3D mural with sustainable birdhouses.

Former headquarters of the KGB.

This often-missed monastery, set in a scenic mountain landscape, features unique frescoes, fortifications and legends.

London’s first road overpass is so old that it was originally built for horse-drawn carriages.

Preserved 19th-century lime kilns sit in southern Sweden.

This cemetery of rusting Soviet-era steam locomotives and train cars offers an apocalyptic glimpse into a bygone era.

Local legend has it that the Devil's claw marks are etched into this distinctive rock.

Seven dragon statues—including one that breathes real fire—are scattered throughout the streets of Krakow.

Legend holds that this knife serves as a chilling reminder of the deadly rivalry between two local builder brothers.

There's something in the air as history repeats itself at this museum dedicated to the Swedish pop band.

Opened in 1787, this old-world treasure is said to be the oldest restaurant in Copenhagen.

A memorial dedicated to the 29,000 Istrian freedom fighters of World War II.

One of London's lost rivers runs through a pipe over the tracks of this subway station.

This sculptural representation of an Andersen fairy tale had to be pushed away for being too grim.

An excavation site that signified Hercules in Pula, and a glimpse into the city's Roman history.

These hilariously laughing bronze figures lampoon empty promises while encouraging civic engagement.

According to local lore, a flying dragon was blinded by a lighthouse and crashed, leaving a permanent mark on this island rock.

This colossal hiking boot, once built for a scout jamboree, serves as an observation tower and barbecue area.

The former Nazi Germany concentration camp stands as a museum to remember this dark chapter in European history.

An artificial hill and apparent calendric structure built in the Early Middle Ages immortalizes a legendary Polish princess.

This man-made mound monument was built out of soil from all across the Polish empire.

There are thousands of tributes and memorials to the King, but none quite like this one in a Kraków city park.

At first glance, this area seems like just another city park, but the lush landscape hides a dark past.