The heroic sled dog of the 1925 serum run is preserved in taxidermy.

A medieval military street hidden beneath a charming French fishing village.

This ancient Roman bridge and aqueduct still stands as a wonder of classical construction.

This ancient theater was once the home of fierce gladiatorial battles.

A unique underground structure dating back to the 1st century BC.

This stunning concert hall has become a symbol of Iceland's national recovery.

Iceland's largest geothermal mud pool is a little bit haunted and a little bit dangerous.

Literally a million fascinating cartographic artifacts are held in this sprawling university collection.

Walk in the footsteps of the gods and straddle two tectonic plates.

A giant, Gilded Age mansion that once belonged to the beer baron of Milwaukee.

The spot in the Mile-High City that's exactly 5,280 feet above sea level (at least for now).

The final resting place of American icon Buffalo Bill, and a museum that aids in telling his tale.

Descend 2,030 years into the past in an ancient tunnel built to support Jerusalem's most famous wall.

This tree was extinct for a thousand years before sprouting again from a 2,000-year-old seed.

Abandoned since the 1950s, the streetcar lane beneath the heavily trafficked bridge lays empty and unused.

Funded by John D. Rockefeller, this is one of the earliest, and most beautiful, shopping arcades in America.

The only depiction of Abraham Lincoln holding a weapon, and the names of all 9,000 Cuyahoga veterans of the Civil War.

This spectacular public market has got meat, fish, vegetables, baked goods, and enough kielbasa for a lifetime.

Ruins of the elaborate house where the enigmatic costume designer threw glamorous parties for New York's theatrical elite.

The oldest surviving bridge in New York City, which reopened to pedestrians in 2015.

Cleveland's giant "free" stamp is a nod to the Civil War, but was misinterpreted for years.

A rare chance to get up close and personal with a 13-mile ribbon of ice near downtown Juneau.

Ghost stories surrounded this “castle,” the only structure from a huge mansion that was never built.

Discovered by cows, these upstate New York show caves are presented with a healthy dose of psychedelic folk art.