This Stockholm art museum integrates many of its pieces into the surrounding outdoor areas and natural landscape.

In 1927, a biplane disappeared while attempting to complete the first non-stop transatlantic flight between Paris and New York City. This memorial stands at the last place it was seen.

This massive metal sculpture in the shape of a folded paper airplane overlooks a Utah mountain.

A museum run by retired highway engineers who helped rebuild after the Great Hanshin Earthquake.

Designed as a reminder of one of the darkest moments in Austrian history.

Unopened beer cans are left at this monument to honor the Navy men who lost their lives during a training mission.

It’s all about the Benjamins at this Atlanta museum with interactive exhibits.

Cooled, fractured lava formed this geometric rock feature.

This Colorado fire station has been in continuous operation for more than a century.

This stone monument marks the beginning of Portugal's presence in Brazil.

William Buckley escaped from prison and is said to have spent years hiding in this seaside cave.

The equator passes through this tiny island in the eastern Atlantic.

Once the smallest park in the national system.

A granite plane marks the site where a French aviator completed the first airplane flight across the English channel.

The only remaining sod house Oklahoma built by a homesteader in 1894.

In the hometown of the Catholic saint and Nobel Peace Prize winner, a memorial dedicated to her legacy.

A relic of World War I that now exist as a piece of public art.

Dedicated to a U.S. Army lieutenant colonel who was also a bird watcher and artist.

Irontown was founded in 1868, as a second attempt to mine iron from the nearby Iron Mountain.

Despite the name, it's unclear if this small depression in northern Nye County was actually caused by falling space debris.

This sandstone building is a relic of the Overland Trail.

A museum dedicated to secret surveillance.

The lobby of this hotel near the U.S.-Mexico border features a stained-glass mural that measures 42 feet long and 6 feet tall.

Danish whalers once brought back whale bones to use as building materials in places where wood was scarce.