A Texas cave network is home to some of the world's most spectacular-looking and bizarrely named mineral formations.

This natural wonder drops 16 stories straight down through rare flora and streaming waterfalls.

Medieval irrigation channels built into the sides of mountains provided Valais with water for hundreds of years.

This abandoned fishing settlement may well be the greenest village in the world.

An enigmatic natural rock formation with a manmade passage cut through the center.

The world’s oldest and biggest bookstore stocking only mystery, crime fiction, espionage, and thrillers.

This stunning natural double arch, the largest in the Alps, went undiscovered until 2005.

A remote forest of stone pillars along the Lena river.

A modern tower, symbolizing the legend of a golden egg on top of the tree of life.

This functioning parish church is also the site of many concert performances due to its wonderful acoustics.

The world's first ice hotel is still one of the most elaborate and beautiful.

A series of modernist treehouse hotel rooms grace the outskirts of an Arctic forest.

This lake-bound geographical marker sits at the point where three European countries intersect.

In legend, this ancient dolmen was said to have been created when a troll tried to destroy a church.

One man's exploration of the human form, including the bizarre and delightful "Man Attacked by Babies."

The world's oldest individual clonal tree looks like a wimp despite standing tall for 9,550 years.

Monuments don't get much more metal than these three giant viking swords planted in a Nordic hill.

Remains of the artificial harbours invented for the Allied invasion of Normandy can still be seen at sea.

This historic stone gate tower is now just a lonely relic in the middle of a swamp.

Small French town or alien garage?

This Corsican Neolithic site is full of pre-Roman megalithic structures that may or may not be penises.

One of the largest ochre quarries in the world, hidden in a limestone landscape.

This salt marsh in Southern France is as pink as the flamingos that inhabit it.

A well-preserved medieval village nested on a rocky outcrop and surrounded by a network of cliffs, natural bridges and canyons.