A plaque bearing the names of those who dedicated themselves to protecting Budapest's Jewish population during World War II.

During World War II, Austria's oldest salt mine was used to store thousands of pieces of stolen artwork.

A Norwegian-born sculptor created these soaring guardian angels at the entrance to Hoover Dam.

One of Canada's oldest collections of stone fur trading buildings.

This former POW camp was transformed into a Cold War missile installation.

Rusted and decayed, this former mining site is a portal to the past.

Planes, helicopters, and a shipwreck are underwater in this former limestone quarry.

This colorful gate stands as an entrance to the walled city of Old San Juan.

This rock in the middle of a river in Jayuya contains dozens of Pre-Columbian Taíno petroglyphs.

Ute tour guides have been sharing the ancient dwellings and rock art inside this large park with visitors for more than 40 years.

This Roman underground canal was the longest tunnel ever built until the late 19th-century.

This picturesque cottage was the site of Ulysses S. Grant’s final and perhaps most important campaign.

Images chiseled into the basalt here date back an estimated 300 years.

Now overlooking the Home of the British Army, this gargantuan statue was removed from its original location in London.

A stack of stones steeped in Irish folklore, much like the hero they're connected to, hide in plain sight.

This statue of a Red Army Soldier has been moved and changed several times since its creation.

A striking memorial to the 21 lives lost in an explosion at the Washington Arsenal

Walk into an underground archeological dig, the site of the Roman Forum that was once the center of Valencia.

The oldest known metal-mining site in England dates back to the Bronze Age.

A monument to the bloody fight against fascism in Slovakia during World War II.

Nine caves filled with recently-discovered archaeological finds under the houses and the streets of the most ancient district of an old town.

This church houses the tomb—but not the remains—of St. Nicholas, the likely progenitor to Santa Claus.

A Lycian city of the dead carved into the hillside of Southern Turkey, complete with startlingly human touches.

A mysterious ancient cemetery with Roman sarcophagi and Lycian inscriptions.