Hundreds of lucky felines haunt the ruins where Caesar was murdered.

Final resting places of a husband and wife who became famous for their claims of extraterrestrial abduction.

Annual celebration commemorating the 1965 sighting of strange lights in the town.

A former zoo turned public park, where visitors can hang out in the old animal cages.

Stumps of an Ice Age forest, visible only at low tide.

America's oldest archaeological site or a muddled case of wishful thinking.

Even Henry David Thoreau found this glacial pothole irresistible.

Despite its extensive history, this fort saw little to no combat.

The once-abandoned 140-year-old hotel used in the movie "In Dreams."

One of 100 “Whaling Wall" murals painted in 13 different countries by a renowned marine life artist.

Once the future of underwater combat, this old sub is now open for visitors to muck around in.

Model Trains and Much More in Hamburg.

This scale model of our solar system hid in plain sight for years before a physics team sought out all the planets.

This 135-year-old weather station studied the effects of the climate on human health.

A World War II evacuation tunnel turned into a history display of Croatian state and people.

An eclectic art form practiced by untrained masters is celebrated at this museum in the heart of Zagreb's old Upper Town.

Where the lovelorn find a home for their sentimental keepsakes.

Once a state-of-the-art tuberculosis treatment spa, these ruins are now ruled by paintball players.

A mysterious, abandoned building rotting on the Brooklyn waterfront.

This hidden green space is the city's second largest conservatory.

The remains of Crystal Palace Great Exhibition of 1851.

Hear the quietest sound from across the dome.

A little slice of Japan and its aesthetics in London's Holland Park.

Catacombs turned marketplace.