Behold the rickety wooden glory of the world's oldest operating roller coaster.

This "floating railway" is one of the world's oldest monorail systems.

A marvel of Byzantine engineering under the streets of Istanbul.

1513 Turkish world map, full of European state secrets and snarky commentary.

No one is sure if the world's fourth-largest diamond had been found in a rubbish heap or was pawned by Napoleon's mom.

This former Imperial summer home was the venue for a royal slap that once echoed 'round the world.

The plague quarantine island home to the alleged "Vampire of Venice."

This abandoned island off the Venetian coast has been a radical monastery, a political prison, and a secret Nazi base.

Public works and national defense project meant to carve a canal all the way across the state of Florida.

This ancient octopus-like tree was saved from destruction thanks to shady reporting.

The oldest botanical garden in the world that technically isn't the oldest.

A complex, nine-layer maze on the grounds of a Venetian doge's playground.

A modest museum in the final home of Italian poet and father of modern Italian, Francesco Petrarca.

The world's oldest surviving anatomical theater, where "the dead are pleased to help the living."

Built to repay the sins of the father, this church is home to one of the most valuable works of Western art.

Venice's "Island of the Mad."

As can be expected from a centuries old church built in a canal city, the undercroft of this house of worship is beautifully flooded.

An unrealized dream to wirelessly electrify the entire Earth.

Lombardy poplars planted to imitate the size and shape of the Cathedral of Notre-Dame de Reims.

A curious collection dedicated to human and animal anatomy and pathology.

This still-celebrated home was a radical architectural experiment in 3D De Stijl.

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

A beach made of semi-precious green sand on the Big Island of Hawai'i.

A nearly 500-year-old sculpture depicts a man eating a sack of babies, and no one is sure why.