Presented to the city in 1910 for public use, these brass markers show varying lengths.

This remote island in Iowa was abandoned after being devastated by flood.

This lake in the Cascades lives up to its name, disappearing down a hole every spring.

This charmingly homemade amusement park has been growing for 40 years.

Hollowed out cedar log tubs set in an ancient towering forest.

The seamy, underground secrets of Portland's criminal past.

The eerie remnants of an ancient forest were hidden under the sand for centuries.

Oregon's unexpected high desert, displaying layers of time in a colorful show.

The magic's in the hole!

No one knows how this Pacific Northwest spruce tree came to have so many trunks.

A heavenly experience, right here on Terra Firma.

This frequently-photographed waterfall takes only a short hike to visit.

A beautiful 62-acre Catholic shrine and botanical garden.

The deepest lake in the United States, and once the site of epic destruction that lives on in legends.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

These old stone ruins in the Oregon wilderness were once bathrooms and are steeped in legends of murder.

On the Oregon coast there is a natural hole that seems to be draining the sea.

The world's largest collection of autographed baseballs can be found at the St. Petersburg Museum of History.

Hidden within an idyllic suburban garden is a memorial dedicated to the victims of a terrifying spree of killings committed on U.S. soil.

The easternmost town in Alaska can only be accessed from Canada.

The first presidential bomb shelter was located in an old vault under the Treasury, connected to the White House via tunnel.

Disks are rolled out onto the south lawn to absorb the impact of Marine One's wheels like giant coffee coasters.

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.

Buy a token from the liquor store and you can make this beast spew flames on command.