An ornate private entrance to the Vienna subway built specifically for the emperor.

Easily overlooked in favor of the wineries that dot the region, this blast from the past is equally worth the visit.

A labyrinthine network of chambers with a storied past hides below Edinburgh's South Bridge.

The 1940s structure houses what was once Europe's largest telescope.

A solemn, monumental, kitschy palace of worship honoring victory in the Great Patriotic War.

Also known as Napoleon's Canal, this waterway was created on the orders of the general, and construction was interrupted by Waterloo.

Designed by a computer, this intricate network of fluorescent green pipes has taken over a subway station.

According to tradition this is the oldest church in Venice, but its actual age is a mystery.

This Chinese art gallery is hidden inside the Sunrider Corporation headquarters.

A stunning medieval castle houses this eclectic, interactive tribute to all things wine.

A whimsical museum dedicated to the mischievous kappa, a mythical cucumber-loving water sprite.

These little-known sands dunes are a geological anomaly in Saskatchewan's southern prairies.

This Russian bar-restaurant lies within a three-story underground bathhouse.

Legend says the only thing buried within this magnificent tomb was a dog.

Now a memorial to merchant sailors and Titanic victims, this medieval church was destroyed by bombing raids in 1940.

This Cape Cod museum exhibits what it claims is the only authenticated pirate treasure in the world.

Constructed by forced laborers, this submarine pen is now a museum and war memorial.

The ruins of an ancient fortification wall sit in front of and underneath this boutique hotel.

This small gallery nestled inside an old botanical glasshouse is a quiet place to enjoy art and nature.

Amidst towering office buildings, a local pub lives inside Sheffield’s oldest surviving domestic building.

Nestled atop a wind-swept crag in the Scottish Highlands is a lonely memorial to a beloved hiker.

A catapult rock from Gotland’s 13th-century civil war is still lodged in Scandinavia's best-preserved medieval city wall.

Known locally as the Jungfrutornet, this Medieval tower hides a dark legend.

This trio of stone spires claims to be the only preserved medieval execution site in Europe.