This mountaintop lake bubbles and steams in a perpetual boil, thanks to its direct link to the Earth's interior.

The world's most charming instant portrait studio also happens to be its smallest.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

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

The largest wine cellar in the world is a 150-mile network of underground caves near the capital of Moldova.

A hotly contested micro-nation off the coast of Montserrat.

A trailblazing sovereign nation tucked in the American state of Wisconsin.

A proto micro-nation sometimes populated by artists, surrounded on all sides by a Utah most barren.

The smallest country in Australia is a principled little thing with a friendly emperor.

This massive blockhead sculpture hides an entire library.

A muddy alien landscape that is home to rare species of exotic plants.

Check out engineering marvels of the past at this unintentionally retrofuturist museum.

An extraordinary collection of scientific instruments - and Einstein's chalkboard - inside the world's oldest purpose built museum building.

Collection of antique science instruments displayed in recreated 1870-1930 laboratories.

Museum houses an impressive display of the origin and artistry from the now-quaint invention's history.

Experience a quartz crystal sound bath inside a storied, all-wood sound-chamber.

A spherical "micro-nation" in the heart of Vienna.

Modern art meets modern convenience in possibly the world's most architecturally important public bathroom.