Resonant stone, that has been played since prehistoric times.

The building's fluid, wavelike walls are a true feat of architectural ingenuity.

Home to nearly a third of the world's mud volcanoes, Azerbaijan is home to a messy, bubbling, and sometimes explosive landscape.

A gigantic collection of teeny, tiny books.

Climb to the top of its spiral spire for spectacular views of Copenhagen.

Plaques celebrating Lithuanian writers freckle a wall of this picture-perfect path.

This mysterious but iconic tapered tower appears in many Azeri fairytales and legends.

An ornate private entrance to the Vienna subway built specifically for the emperor.

This underground transport hub doubles as an art gallery.

A 300-kilogram egg sculpture that embodied a neighborhood revival.

In downtown Oslo, a menacing and terrifying relief clings to a church wall.

Site of the first radio and telephone broadcasting companies in Copenhagen.

An early 20th-century bullring converted into a modern shopping center.

Time stands still at this serene burial ground in the center of Budapest.

Nine bronze hands protruding from a wall honor the student uprising that led to the fall of Czechoslovakia's Communist government.

The biblical sculpture honors those who lost their lives, homes and communities to the Chernobyl disaster.

The first modernist church in Europe.

Also known as the Blue Church, the building was consecrated to the daughter of Andrew II.

Legend says this mysterious stone head belongs to a woman who was petrified by an alchemist.

This enormous abstract sculpture is part jungle gym, part elaborate noise-making machine.

This spooky statue sits outside a famous Prague theater.

The floor of this spectacular Baroque sanctuary is covered in memento mori.

The oldest museum in Russia is home to a fascinating collection of nearly two million anthropological artifacts and anatomical curiosities.

An abstract monument to a symphonic composer.