An unfinished tomb carved into a giant boulder in the Arabian Desert.

Roadside collection of 65,000 signs.

The bomb-ravaged remains of of a colossal Neptune.

The oldest church in the Estonian capital is home to over 100 fantastical cemetery coats-of-arms.

The world's second-largest sundial, made entirely out of stone.

This collection of solar timekeepers includes the world's first digital sundial.

Fascinating museum dedicated to the under-appreciated medical history of urology features some wince-inducing devices.

This submersible road connecting a French island to the mainland is lined with safety towers for when the tide strands travelers.

One man's quest to collect artifacts from every aspect of human life has resulted in this eclectic Argentinian museum.

Hidden within a Netherlands crater is a stone bed that lets those who lie in it see the sky as a curved surface.

This impressive tunnel was dug entirely by hand over the course of 36 years.

These crumbling Nazi artillery bunkers are now fair game for massive graffiti projects.

These ancient ritual mounds are our best window into the culture of the ancient Mississippians.

The vast chamber inside this abandoned cooling tower looks like something out of a sci-fi dystopia.

This German art chapel is perfect for those who like their worship hard, modern, and utterly alien.

A new kind of theme park for adults off the Las Vegas Strip.

Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

This former Norwegian sailor's church is slowly being taken over by ramshackle robot musicians.

An indoor miniature village and labor of love for Laurence Geiringer, a model railroad enthusiast.

She asked for a potato cellar and over the next 23 years he gave her a network of holy caves.

The wooden octagon in which Huckleberry Finn and A Connecticut Yankee were born can still be visited in upstate New York.

A bizarre house filled with an astounding array of collections.

What once claimed to be the world's tallest single-family wooden structure house.

Experience park where visitors are told to expect the unexpected.