Burial mounds of prehistoric Native Americans who lived along the DuPage River.

The final resting place of the world's first nuclear reactor.

19th-century operating theatre in which the use of ether was first demonstrated - plus, a skeleton and a mummy!

These underground shelters dug by the Japanese during World War II later helped East Timor achieve its independence.

Walled family complexes in Southern China.

A 1,500-year-old, 3-story subterranean city where ancient Persians took refuge in times of war.

The spot where the fascist dictator made some of his most famous speeches including declaring war on Britain and France.

Ancient ruins hidden underneath a modern luxury hotel.

An ancient Egyptian obelisk is now used to commemorate fallen Italian soldiers.

Before it was buried by volcanic ash, this fast-food restaurant fed the hungry hordes of ancient Rome.

In the early Roman Empire, people deemed traitors and criminals were tossed to their deaths from this rock.

Rome is now home to a stunning food museum and library.

Inside this McDonald's you can dine on your Big Mac and fries next to a 2,500-year-old Roman wall.

A replica of the Statue of Liberty watches over the tomb of 72 Chinese revolutionaries.

A shrine to the missionary who first brought Islam to China.

Three floors above a 2,000-year-old royal tomb is a rare collection of ancient porcelain pillows.

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

This small museum is home to some of the oldest and best-preserved dinosaur specimens found in Montana.

A scenic ravine with an astounding collection of rock art created by the Indigenous people of the Great Plains.

The bullet-riddled wall from the St. Valentine's Day Massacre, bloodstains enhanced for your viewing pleasure.

Not only does this library house unique Arabic manuscripts, but it was also designed to keep the building cool during warm days.

Half-hidden by grassy slopes, this striking Spanish colonial fort is now a museum of underwater archaeology.

This ruined fort and statue are a testament to the last king of Kaua‘i’s savvy diplomacy skills, which briefly brought Russians to Hawai‘i.

When new viceroys were elected, they passed through this arch to cement the title.