Once the largest unsupported dome in the world, beating out the Pantheon and St Peters in Rome.

An underground city of salt.

A striking symbol of the Bulgarian capital.

This Victorian-era public house has set the standard for pub-style elegance for over a hundred years.

A Trabant car, a kangaroo statue, and a plethora of plants take over this abandoned-factory-turned-bar.

A random tree outside a Budapest hotel has become a DIY shrine to the late singer.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

This one-time health resort was used by aristocrats around the world.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

Pilgrimage site for star-crossed lovers.

A striking 12th-century-style castle built on the edge of a cliff.

The star-studded street honors the city's most notable Brummies.

The last occupied troglodyte dwellings in England weren't abandoned until the 1960s.

An 18th century monument regularly tagged with unsettling graffiti referencing a 1940s unsolved murder.

The lavish, well-preserved home of a wealthy Baba Nyonya family is now a cultural museum.

Singapore's landscaping project is home to 18 incredible Supertrees.

The anatomical-pathological collection of a man who changed surgery.

The curios of pharmacist and collector Henry Wellcome.

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

A kaleidoscopic warehouse-maze of handmade neon signs.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

England's most notorious suicide spot.

One fisherman has used his love of pebbles and shore to create a crazy garden of rocky art.

The rotting skeleton of a shoreside fun fair that was destroyed by fire and storms still haunts the Brighton ocean view.