The hidden ruins of a mill that is linked to an attempt to assassinate the vice president of the United States.

Built in 1815, the stabilized ruins of the grist mill and sawmill are now gated, but interpretive displays on the features and functions of the mill preserve its history.

This heritage museum highlights the importance of the dairy cow as a vital part of rural Maryland's past, present, and future.

The only public school for Black children in the region from 1895-1936.

The ruins of an old mill lie in a small ravine along a hiking trail near Little Seneca Creek.

The whole world in one water tank.

Giant acorn-shaped 19th century gazebo from which suburban Washingtonians gazed upon the original "silver" spring.

A huge musical sculpture and other art installations on the National Oceanic and Atmospheric Administration grounds.

Allowing humans and fish alike to migrate from freshwater to saltwater and back again.

A giant Troll lurks under one of Seattle's oldest bridges.

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

Get lost in this haunting fairytale art walk through a man-made eucalyptus grove.

There is no trying to fall in love with this Star Wars fountain, you just do or do not.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

Guns that have been defending San Francisco since 1904.

Beneath the southern end of the Golden Gate Bridge is the “Gibraltar of the West Coast,” a fort built to protect the San Francisco Bay from naval attack.

Canyon walls shrouded in ferns.

This massive redwood tree has a drive-thru tunnel carved out of its trunk.

An extraordinary collection of aircraft and spacecraft on display at the original site of the Boeing Company.

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

This working class sculpture pounds his hammer all the livelong day.

The tech giant built three enormous glass orbs in Seattle so employees could work inside a rainforest greenhouse.

This sculpture forces visitors to confront their relationship with space.

A rare tour of a commercial jet assembly plant, held inside one of the largest buildings in the world.