Allowing humans and fish alike to migrate from freshwater to saltwater and back again.

Dramatic river bend surrounds a natural red-rocked pedestal.

This rugged area of red rocks and arches is often considered one of the most beautiful places on Earth.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

Jurassic Park—A Still Life.

The largest island on the great salt lake is home to curious creatures and strange stories.

Largest man-made excavation on earth!

Bizarre lunar-like landscape with thousands of large stone "hoodoos."

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

An overlooked marble is the only surviving in-place 18th century example of the measurement that changed how we define distance.

A haunting statue called "Eternal Silence" has quite the reputation among visitors with active imaginations.

A strange and haunting monument of unknown origin in the historic Graceland Cemetery.

An enormous park-like oasis, full of famous Chicagoans' graves.

All of Chicago's wood-paved streets are long gone but two alleys remain.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

A mechanized clock where a man fights off a dragon, crab, and rooster.

A daring D-Day assault by U.S. Army Rangers is commemorated atop the high cliffs of this strategic point.

This stunning French estate was so lavish that it landed its original owner in jail for the rest of his life.

The opulent home that inspired Tintin's Marlinspike Hall and the adventures within.

This former “ante-chamber to the guillotine” has been refurbished to illustrate the brutal history of French justice.

A surrealist timepiece by the artist of melting clocks.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.