This historic hub for labor unions has survived the city's changing landscape.

A secret passageway from World War II is now a quirky pedestrian shortcut.

See the rare bloom of the "Queen of the Night" cactus at one of the world's largest succulent collections.

A full-scale sculpture of a mermaid and baby grand piano hidden underwater by David Copperfield.

Stand at the center of this lakefront sundial, and you'll become part of the timepiece.

Over 100 towers were built in Bologna during the Middle Ages, but only 22 survive.

This mystical orb covered in strange symbols is thought to have been used in ancient Greek magical rituals.

This unchanged Victorian park is rumored to have been the inspiration behind Peter Pan's Neverland.

The intended purpose of this unfinished Elizabethan building remains a mystery.

This grand old 80-foot sequoia towers above the buildings in the city’s retail center.

When the public was consulted about a new piece of street art, they naturally asked for an enormous metal dragon.

The ruins of Scottish sea salt production.

This now-deactivated naval base defended the Florida coast for centuries.

Two men built this castle on the Florida coast as an artistic “landscape sculpture.”

An unknown number of cholera victims are buried in two nondescript graves.

One of the best places in Florida to spot rare, carnivorous pitcher plants.

A rare, flower-shaped example of Brutalist architecture in Switzerland.

An underwater statue of Christ blesses the depths off Key Largo.

This landmark building is now a vibrant performing arts space with musical acts from around the world.

One man spent 10 years building a spectacular section of road because no one else would.

The ruins of a once-thriving sugarcane plantation that was burned in the Second Seminole War.

A hidden beach at the end of a tunnel of mangrove trees.

The oldest cemetery of modern-day Athens blends the modern and ancient worlds.

The ruins of New Zealand's largest classical-style church.