Step into the cool deep past and unknown future of who begat who.

Largest collection of mounted dinosaur specimens in the world.

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

A jaw-dropping "megalibrary" that turns book-browsing into a geometric adventure.

Mexico City's residents are being watched by this state surveillance headquarters, designed by architects with a flair for intimidation.

An abandoned NSA listening post on Berlin's "Devil's Mountain."

Home to secret Eastern Bloc spy equipment and the largest stretch of the original Berlin Wall outside of Germany.

The other side is actually green.

This magnificent blue mosque in Afghanistan is surrounded by thousands of white doves.

Planned as the world’s first zero-carbon city, it had lofty ideals—but is only 5 percent completed and aiming for 50 percent carbon-neutral.

This quaint Hungarian railway system is operated exclusively by children between the ages of 10 and 14.

One of the deepest indoor swimming pools in the world.

"You don't need a rocket scientist to build a steam engine, but we've got one." -Museum docent on the credentials of a restoration volunteer.

Narrow-gauge railway with its own personal power grid.

The prototype for all Nazi concentration camps.

This small red school was where Germany signed their surrender during WWII.

This miniature Paris, built out of trash, is one man's two decade labor of love.

The fantastic architectural models of a French traveler.

Theme park featuring miniature replicas of European monuments.

Large miniature theme park with 100-plus models.

A 1:20 scale piece of the Netherlands commissioned by a queen lets visitors take a stroll as giants.

A quarter-scale locomotive wonderland built by one man and his family.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

Tiny historical streetcars wind through a small scale version of Crescent City in this whimsical train garden.