This unique sculpture is often overlooked by pedestrians.

A 130-year-old urinal is the oldest of Stockholm and perhaps all of Sweden.

Small Easter eggs are hidden in the ventilation holes of the city's newest trains.

This gem from the industrial age helps visitors and residents alike traverse hilly Stockholm.

A 12th-century church with a medieval fresco and an intriguing “Greek runestone.”

Outside a Viking museum sits a modern-day runestone made by a Swedish runemaster using traditional methods.

Located in an old church, this brewery produces a different kind of holy water.

The discovery of an old wall led to the creation of this fascinating museum about the city in the Middle Ages.

An ancient Viking runestone hidden in plain view in Stockholm's old town.

Sweden's "good old days" painstakingly re-created in a model village.

Stockholm's deepest subway station is also a stunning ecological wonder.

This Stockholm light tower can be controlled by anyone with a smartphone.

A rare surviving Victorian greenhouse designed specifically to house giant water lilies.

The library's graceful rotunda is like a bibliophile's temple.

Dine on food tied to Viking history and legend at this subterranean Stockholm spot.

Hidden in a grotto 26 feet below Nottingham's oldest hotel, this stylish subterranean drinking den is notoriously hard to find.

Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

A collection of comics, graphic novels, animation and caricatures devoted to exploring this often overlooked art form.

A plaque pays tribute to the artist's longtime London home.

London's old-school healing garden.

The secret wartime bunker built on the platforms of an abandoned Tube station.

A traditional American farmhouse plopped in the middle of a Piccadilly courtyard.

Drink your espresso at a Victorian-era urinal in this underground-restroom-turned-coffee-bar.

The final resting place to 300 Victorian-era pets hides inside the city park.