The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

Pompeii's less famous neighbor is still revealing her secrets.

A fascinating insight into daily life in the Eastern Bloc.

Stalactites and stalagmites in a beautifully lit cave.

An Oxford museum where visitors can have tea with the Mad Hatter and climb through the wardrobe to a fantasy land.

This 22-floor tower's Skydeck offers panoramic views of Amsterdam.

A steampunk-styled three-floor factory churning out art, activism, and electronic beats.

Where once there was a train station bathroom, there is now this German burger joint.

Each spring, a dreamlike carpet of bluebells overtakes the forest floor.

According to the local folklore, the myriad colors of this lake are the result of a lovelorn wizard's blunder.

Houses are tucked between, on, and underneath giant boulders.

400-year-old garden, restored to beauty.

This permanent exhibition celebrates the finest of our heartless automatons both real and fictional.

2300-year-old Roman road connecting the empire.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

A subterranean shelter remains intact under a busy Paris railway station.

This replica of the Greek structure is in the heart of Nashville.

The hallucinogenic center of the ancient world.

The final resting place for the remains of 143 Habsburg royalty.

A series of caves under Castle Hill that once held the prisoner Vlad Tepes, better known as Count Dracula.

A band of aerialists and circus performers putting on incredible shows in East Williamsburg.

Near the former site of numerous witch burnings, this lavish Edinburgh mainstay pays homage to Scotland's brutal history.

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

This cemetery features modernist statues as strange as its name.