A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.

A celebrity from the late Cretaceous period.

A super-sized promotional trick that is now a D.C. landmark.

The walls of the iconic dome are hollow and have a secret stairway.

People escaping slavery may have hidden inside a corpse vault.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

Home to items never before seen by the public.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

Not-so-fearsome tiny trolls live under this wooden train trestle in Portland.

This stoic, if derpy, giant stands as a monument to Oregon's statehood and the novelty culture of yesteryear.

The U.S. Navy's last diesel-electric submarine rests half-submerged in the middle of Portland.

Tiny horses tethered to antique rings are scattered around the city.

This public art piece proves that in Portland even reporting the weather is a thing of whimsy.

A sculpture of a salmon swimming through a brick building.

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

A delightfully quirky blend of oddities spread throughout an old 1920s bank.

A local farm's collection of unusual structures from a now defunct storybook amusement park.

Remnants of a storybook amusement park hidden behind a strip mall.

A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

A sculpture for the sun and stars, created by Nancy Holt.

The original place where water met land in the City by the Bay is outlined in brass.

Community bookshelf of 25-foot-tall book spines.