An emerald-green grotto just a short trip from Austin.

This unique structure in suburban Austin is made up entirely of other people's castaways, and constantly changing.

This historic "City of the Dead" lies prominently in the center of New Orleans' famous Garden District.

An impressive collection of dollhouses and an homage to the frog-leg canning industry.

Formerly known as National D-Day Museum, this collection commemorates the battles of Normandy and WWII.

A small park on Bourbon Street features life-size bronze statues of New Orleans musicians.

Shop for books in the New Orleans house where William Faulkner once lived.

A museum and shop on Bourbon Street located in the former home of the second Voodoo Queen of New Orleans.

A snapshot of the city's fascinating voodoo culture.

This failed condo development was reborn as a street art hub.

Continuing the tradition of the dime museum in style.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

Locals dubbed it the "Owl Building" because of its bird-like appearance.

Spanning the El Chorro gorge, this pathway used to be one of the most dangerous crossings in the world.

The two massive guns that defended Cartagena Bay.

A church filled with the bones of hundreds of virgins martyrs—or so they say.

Skulls from the plague of 1656 and World War II bombings are united by a cult dedicated to caring for the ancient dead.

An enormous steel waterfall is a nod to the substance that shaped Britain's Steel City.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

Elaborate tile work in this railway station tells the story of Portugal.

The verdant mossy ruins of a Franciscan monastery lie in the remote Sintra hills awaiting exploration.

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.