This church was constructed by a shipbuilder and designed like an upside-down boat.

This shale formation along the Appalachian Trail once inspired the third president of the United States.

An abandoned bear enclosure from a 19th-century zoo located in a Danish forest.

This lookout tower built in the 1930s is now an in-demand cabin with what might be the best view of the Seneca State Forest.

A lighthouse on this West Virginia lake started as a joke, then the forces of nature helped make it a reality.

Get up close and personal at this Fresnel Lens.

A 60-foot-tall tower provides unparalleled views of the southern Green Mountains.

This former fire tower is now a rustic observatory that offers amazing views of eagles, hawks, and the Appalachian Mountains.

This elaborate High Victorian Gothic structure is one of the world's few 16-sided buildings.

A relic of the Cold War in Chicago.

A busy island at the center of the world that doesn’t actually exist.

Doris Duke's lasting collection of Islamic Art, hidden in a Hawaiian paradise.

Once home to over 8,000 exiled Hawaiians suffering from Hansen's Disease.

This ancient Hawaiian henge may have been an early star chart.

The island of Lanai in Hawai'i is a paradise for cats and cat lovers.

A lightship turned museum, outfitted with artifacts from the vessel's past as part of the U.S. Lighthouse Service.

A somber memorial honors the hundreds of thousands of lives lost at this labor and extermination camp.

This stucco building in North Africa was the first American-owned property on foreign soil.

An abstract representation of weather in Sweden.

From battleships to Roman vessels, this museum explores the depths of shipwrecks in the region.

A small Second Empire-style building is one of only seven remaining lighthouses on the Hudson River.

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.

Built to defend Washington D.C. during the Civil War, this fort became a post-war nucleus for a thriving Black community.

This monument is dedicated to those lost on June 6, 1944, in the town with that day’s highest per-capita casualty rate.