This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.

A Nesting Doll of Churches.

Jesus' footprints and the first catacombs in the world.

Sitting on an Italian hilltop is this surreal fortress built by the mad inventor of electrohomeopathy.

Geothermal waterfalls in Tuscany.

Thousands of well-dressed mummies below a monastery.

Architectural monsters are devouring this palace's every door and window.

Drink wine handed out through a window as part of an age-old tradition.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

A striking bronze sculpture of a Roman goddess with two hound dogs for company.

Australia's oldest artists' colony.

A unique rock formation that only a few have managed to venture inside.

This classic photo booth was saved from destruction by the local community.

One of the youngest volcanic eruption sites in Australia.

An opulent mansion that acted as the set for Appleyard Girls School in the 1975 classic film 'Picnic at Hanging Rock.'

This former psychiatric hospital was once one of the largest in Australia.

Hundreds of tiny dead butterfly eyes gaze down at diners in this Australian eatery.

A small curiosity shop with items ranging from antique medical supplies to taxidermied animals.

Native Australian lizards inhabit this garden celebrating Sydney and its sister city in China.

Tiny artwork tucked within glass letterboxes form this hidden gem of an art gallery.

A remarkable lifelong collection of antiques and art preserved in a historic Melbourne townhouse.

The 18th-century home was disassembled into 253 cases and brought all the way from the other side of the world.