The Victoria-era quarantine station for Sydney.

This historic observatory contains the world's oldest refracting lens telescope.

The labyrinthine storm tunnels beneath the city of Melbourne are ruled by a band of urban explorers.

One of the world's tallest Ferris wheels takes visitors high above Las Vegas in a spinning party room.

The bones of two medieval royal lions were discovered at the historic fortress.

An architectural oddity hides in plain sight on this iconic London bridge.

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

This long-hidden space above Westminster Abbey now displays the battle gear of the legendary King Henry V.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

Look closely and you’ll notice that the color changes a third of the way up the tower.

Washington's iconic carousel has a nice piece of Civil Rights history.

D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

This historic graveyard was partially paved over to create a streetcar line.

One of the largest trees of its kind in California.

San Diego's most historic and haunted home.

This university transit system is a 1970's vision of the future.

The world's largest fully steerable radio telescope.

This rural community has attracted both scientists and techno-refugees due to its federally-mandated lack of technology.

Take a steam-powered ride straight out of the past on this Appalachian rail line.

One day a year it is legal to jump off of this astoundingly tall bridge that spans an Appalachian gorge.

The "mysteries" of this quintessential roadside oddity were almost destroyed by neglect but were saved by fans of kitschy wonder.