The second-largest giant sequoia in the world.

A tunnel that brings more than a century of history to life from the deepest parts of the Niagara Gorge.

Two craters, which probably erupted within the last 1,500 years and are now filled by alkaline lakes, represent Nevada's youngest known volcanic activity.

This wilderness hike to a waterfall has an unlikely beginning in suburban Reno.

In 1954, two enormous earthquakes occurred just minutes apart, resulting in prominent scarps that extend for miles along the range fronts.

The tallest bridge in California was constructed for a project that was eventually cancelled.

A train tunnel that was made obsolete by the dam it helped create.

On October 26, 1963, a 12-kiloton nuclear device was detonated here in granite some 1,211 feet below the ground surface.

A showcase of engineering might that was also symbolic of westward expansion.

California's first suspension bridge.

Also known as "Robin Hood's tree," this tree became a famed location along Hadrian's Wall before it was cut down in an act of vandalism.

A double cantilever system bridge that was designed to prevent flood damage.

A human attendant once directed car traffic from this structure before automated stoplights.

A small Wyoming town is home to the state's oldest-operating soda fountain.

A tunnel with windows, so you don't miss out on the impressive views.

The decaying ruins of a failed mining company’s water diversion project cling to the side of a desert canyon.

Its collection includes a broad array of social, geographic, graphic design, and political history.

The arch that celebrated the completion of the Lincoln and Victory highways.

All that remains of the once-booming chain is a single orange-roofed restaurant.

A lone tower rises above the cliffs in a city park, offering fantastic views of the Connecticut landscape.

The fantastic charm of England's oldest botanical garden has made it a place of writerly inspiration for centuries.

The oldest orange tree in California spawned a generation of citrus farmers.

After nearly 60 years, there's still a bear at Paddington Station looking for help.

This railroad magnate's 19th century tower is more than a little bit out of place in the Nevada desert.