This ruined fort hidden at the top of Central Park can't seem to keep from losing its historical plaques.

Throughout this shopping mall are medieval ruins that were discovered during the mall's construction.

This spooky statue sits outside a famous Prague theater.

A surreal statue honoring Prague's favorite literary son.

An existential riddle in the world's largest ancient castle.

Despite attempts by local police to discourage it, Beatles-inspired graffiti has been a means for artists to air grievances for decades.

Walk through Czech history in Prague's largest graveyard.

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.

A favorite with sightseers, this Norwegian funicular provides easy access to a stunning view of Bergen and its environs.

The Brutalist building harbors an unusual inverted dome that swoops down over its central sacred room.

One man's exploration of the human form, including the bizarre and delightful "Man Attacked by Babies."

Home to three historic ships from the age of Vikings.

A beacon atop a downtown building provides Bostonians with weather forecasts and baseball news.

What was once a true peninsula has now been filled in, causing the water to recede and leaving many streetside "waterfronts" and landlocked "islands."

The strikingly modern structure stands out among the brick buildings speckling the Harvard Business School's campus.

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

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

This monument on Breed's Hill proves that one of the most famous battles of the Revolutionary War is misnamed.

The Boston square dedicated to the dark poet who was born nearby.

This unique architectural wonder is also tied to one of the 20th-century's most renowned writers.

The best place in the world to buy tinned fish.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”