A mysterious crater-like pond has a spooky tendency to empty and fill with complete disregard to rainfall patterns.

The most powerful waterfall in all of Europe.

This Big Sur waterfall drops 80 feet directly into the Pacific Ocean, and inspired the hillside house up top.

This rare example of a "tidefall" is a spectacular drop from the cliffs down onto the beach.

The hidden "ballroom" under a mansion lake was built by a criminal who ate a cyanide pill during his trial.

2300-year-old Roman road connecting the empire.

Bonsai trees that are up to a thousand years old.

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

These beautiful objects represent beautiful ideas.

A half-mile long and three stories high, this bridge over the Des Moines River Valley mimics a descent into a mine shaft.

This giant Massachusetts sycamore is said to hold the dubious distinction of being the "widest tree East of the Mississippi!"

A mysterious pair of mice eating a piece of cheese is London's smallest public sculpture.

A shop full of natural curiosities, carnivorous plants, and costumed taxidermied mice.

This picturesque Umbrian city has a subterranean side that has long remained hidden.

The stately remains of Llywelyn the Great's mighty fortress.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

The oldest family-run luncheonette in New York, last renovated in 1948, still serves food and drinks the old-fashioned way.

Site of a famous 19th-century transcendentalist utopian community, now abandoned.

The often-overlooked ruins of one of the first buildings designed by famous landscape architect Frederick Olmsted.

The "Skinny House" is made from scrap, salvage, and a neighbor’s kindness.

A grandiose octagonal home crowned by a large dome stands out among the antebellum mansions.

An optical Illusion once believed to be an electrical phenomenon.

Possibly the oldest living thing in Europe, more likely a pagan survivor.

The ruins of this gorgeous clifftop castle look like something from a fantasy novel.