This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

There was a top secret plan during World War II to seal a group of soldiers inside the rock.

I-95's Tijuana-style celebration of kitsch at the Carolina border.

This South Carolina water tower is an icon of the city of Walterboro, but it also once served as the county jail.

South Carolina's last remaining slavery auction house is now a museum devoted to its own tragic history.

This blowhole is supposedly caused by a trapped monster.

A tunnel of hardened lava along Maui’s famous Road to Hana.

Take shelter from Hawai'i's tropical heat under the massive canopy of largest Banyan tree on the island.

Museum of Fijian history, including its former tradition of cannibalism.

Earth's tallest volcano is sacred to Native Hawaiians, and home to a dozen world-class observatories.

A museum now occupies the mansion in Samoa where the prolific Scottish writer chose to spend the last years of his life.

Coastal dunes, site of buried Egyptian movie set and former utopian colony.

One day a year it is legal to jump off of this astoundingly tall bridge that spans an Appalachian gorge.

The ruins of this Thomas-Jefferson-designed mansion have been left to crumble since the Christmas Day they burnt down.

This historic mansion was built as a symbol of love between a husband and wife.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

This stately building in Alexandria, Virginia was built by Freemasons to honor one of their most famous members.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

Largest Roman Catholic church in North America.

Home to items never before seen by the public.

A former major munitions plant that has been converted into a sprawling art space.

A vertically floating hemlock controls the waves and weather at Crater Lake.