A rotting tree in the middle of Seattle doubles as an elaborately-controlled art piece.

Go inside to really appreciate this 500-year-old technological masterpiece.

This playground sculpture of an icon from the past is dedicated to the children of the future.

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

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

Train debris from the deadliest avalanche in United States history can still be found in the ravine where so many perished.

Few other hotels can rival the grandeur of the Castle in the Rockies.

Macabre headstones carved with winged skulls, dancing skeletons, and pithy reminders of impending death.

The only road through the heart of Glacier National Park.

Milan's duomo is covered in beautiful carving including a curious "dinosaur-like" beast.

Elevated freight railway turned wildly successful urban park.

The largest wooden building in the world now houses a fascinating collection of aircraft.

This strange bovine gargoyle is said to have been put in as a passive aggressive form of revenge.

A walk through the historic city center, under the streets of Seattle.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

The final resting place of one of the most sensational guitar players of all time was created only after his father got the rights to his music.

A centuries-old church stands as a testament to Boston's "father of architecture."

This area was once known for being a lawless haven for rough-and-tumble sailors, earning the maritime-themed nickname "the black sea."

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

Equal parts record-breaking temple to consumerism and bizarre fun park, it's more than you think it is...

A young botanist's horticultural vision realized through a lifetime of planting, tending, and collecting seeds.

42nd story Pyramid shaped penthouse tops Seattle's oldest skyscraper.

Tragedy on Little Brewster Island memorialized.

The oldest working bell set in North America, the bells at Old North Church sat silent for their first four years in Massachusetts.