Berthed at the Charlestown Navy Yard in Boston, "Old Ironsides" is the oldest commissioned warship still afloat.

Macabre headstones carved with winged skulls, dancing skeletons, and pithy reminders of impending death.

This statue inspired by Renoir's famous painting embodies the jovial spirit of Key West.

A monument celebrating the idea of reaching inaccessible places.

The former home of the Nobel Prize-winning American writer is now home to dozens of six-toed cats.

Hear the quietest sound from across the dome.

One part local history, 99 parts gruesome haunted house.

An Oxford museum where visitors can have tea with the Mad Hatter and climb through the wardrobe to a fantasy land.

A Mayan village preserved for centuries in volcanic ash.

This daunting 1st century fortress was purportedly the site of one of the most dramatic revolts of the Jewish-Roman wars.

The largest island on the great salt lake is home to curious creatures and strange stories.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

Iconic red and white plaques show the creative names invented to navigate the city streets.

A hidden treasure of an abandoned city lies deep in the jungles of Campeche, Mexico.

The only castle in North America to ever house European sovereigns.

An elaborate Mayan city shrouded in alien conspiracy revealed the tomb of Pacal the Great.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

Every equinox this Maya pyramid puts on a spooky ancient light show.

Five sultans and their families rest in eternal splendor, teeming with overlooked beauty and drama.

A Turkish ghost town abandoned in a population exchange with Greece.

A marvel of Byzantine engineering under the streets of Istanbul.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

Bridge that died in war and was resurected.

A towering spire in the fortress of Kalemegdan honors the victorious armies of Serbia during their struggles against the Ottoman Empire.