An Inca spa, military outpost or maybe… both?

This ancient structure is widely thought to be the oldest intact pyramid in the world.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

Go take a picture with the inventor of the daguerreotype photographic process.

The house where John Wilkes Booth conspired with his co-conspirators.

The unique traffic pattern named for an influential urban planner is also known as the Pedestrian Scramble.

D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.

The gondolas let you glimpse a bird's-eye view of one of the world's highest capital cities.

A marvel of engineering built to prevent annual floods from devastating the city of Winnipeg.

Seattle's super-sized cowboy apparel once belonged to a themed gas station that wrangled in herds of tourists.

Overlooking the Colorado Convention Center is this giant sculpture made from thousands of triangles.

This beautiful landscape is the only Sichuan-style garden outside of China.

Perhaps the world's only gas station inspired by a political scandal.

Inside this striking glass building, visitors can see thousands of dinosaur fossils in the positions that nature deposited them more than 150 million years ago.

Every drop of water in this 27-mile long reservoir was pumped up from the Columbia River using power from Grand Coulee Dam.

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

This petite park lets visitors see and touch examples of fossilized dinosaur tracks.

This 22-acre botanical garden is home to the largest collection of rhododendrons in the world.

A historic Masonic building overlooking the Puget Sound.

The former home of Samuel Clemens and family remembers the happiest period of the author's life.

An easy-to-miss plaque marks the building that first held this 19th-century telephone innovation.

A tribute to the truly loyal dog who waited outside a hospital for his owner to come back.

An abandoned gun-funded 19th century utopia.

A tiny memorial for the year the Connecticut River almost destroyed New England.