The history of the tea trade is told in bas-relief on this historic pair of Boston doors.

Narrowest house in Boston.

The site where Charles Dickens gave his first public reading of "A Christmas Carol" in the US.

The world's largest piece of copyrighted artwork.

This statue intended for children to enjoy became a minor political spat.

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

Millions of numbers carved in glass represent the tattoos forced upon victims.

These World War I shooting range tunnels are now haunted halls of underground graffiti accessed through the roots of a tree.

Considered by many to be one of the most dangerous highways in Alaska.

This lesser-known Frank Gehry building houses a treasure trove of cinema history.

The abandoned grounds and derelict greenhouses of this once-magnificent Edwardian estate are now a nature preserve open for exploration.

Now housed in a museum, this giant pink elephant stood in downtown Seattle for more than 60 years.

A brutalist gem towering over the heart of Milan.

This sculpture forces visitors to confront their relationship with space.

A large replica of a monumental Roman inscription is located on the side of this museum.

A perfect circle of 24 mysterious holes dates back to prehistoric times.

Next to the Leaning Tower of Pisa is a cemetery home to ancient sarcophagi and disturbing murals.

The New York hotel where tragic visionary Nikola Tesla spent his final hours, destitute and alone but for the pigeons.

Once called Winthrop Park in 1889, home to a decidedly sexy tribute to the Monitor vs. Merrimac battle.

Site of the first pathological and bacteriological research facility in the United States.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

Also known as the Temple of Poseidon, this is one of the best-preserved Greek temples in the world.

A towering monument in Spain has proven to be more labor-intensive than initially planned.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.