A hidden bathhouse in one of Stockholm's oldest and busiest neighborhoods is open to anyone who can find it.

Maybe the only restaurant in the world where your seat will be signed by a Nobel laureate.

This giant subway sculpture celebrates the fruit that inspired the theory of gravity.

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

This legendary dessert was served to Nobel laureates for decades.

This museum explores the history of the city's public transportation. Its collection includes the world's oldest preserved electric trolley car.

This German fountain of a legendary apple wine-loving drink thief will spit on you.

Fantastic views and thousands of love locks.

A rare chance to ride one of the few continuous elevators still in operation.

The sweet story of how American cargo planes became known as "Candy Bombers" during the Berlin Blockade.

From Nazi chemicals to the CIA, this architectural marvel has played a fascinating role in German history.

The entrance to this Frankfurt subway station looks like an old tram car crashed into the concrete sidewalk.

After years of being casually peed on by humans, this tree is peeing back.

The Boston home of a conductor on the Underground Railroad.

In 1958, an MIT fraternity pledge laid down on this bridge and instituted a new, unique unit of measurement.

The last remaining 19th-century tenement from Boston's old West End neighborhood.

A plaque memorializes the Boston location of one of the largest nightclub fires in history.

This small glass cube is a peaceful out-of-the-way sanctuary at the busy airport.

One of the indelible moments of the American Revolution took place at this location.

Sacks of potatoes, made of cast stone, mark where the iconic potato sheds once stood along the river.

This nearly 200-year-old restaurant's history includes an exiled French prince, JFK, and a very hungry Daniel Webster.

One of the last remaining World War II Victory Gardens in the U.S. is quietly growing across from Fenway Park.

The site of one of the strangest disasters in history—a wave of deadly molasses traveling at 35 mph.

19th-century operating theatre in which the use of ether was first demonstrated - plus, a skeleton and a mummy!