A massive 1830s industrial site once known as Czechia's "Iron Heart" has been transformed into a playground of science, technology, and art.

A cheeky architectural easter egg.

A giant interactive periodic table with real samples of the elements.

A controversial artwork draws attention to the dark history of Prague's "Suicide Bridge."

Steadily reminding Czechia of its past.

This unusually shaped mountaintop tower looks like a UFO floating over the city.

A bus with a butt and biceps to put Olympic athletes to shame.

This walkway is so narrow it needs its own light to stop pedestrian traffic jams.

An existential riddle in the world's largest ancient castle.

The world's greatest slide descends 18 stories from this looping mountaintop viewing platform.

This doorless 20th-century elevator doesn't stop or slow down.

An eerie, existential museum dedicated to the author of "The Metamorphosis."

A 400-year-old mummified arm dangles from the ceiling of St. James the Greater, serving as a warning to thieves.

The tunnel's elegant proportions keep you snug with no claustrophobia freak-out.

Buried five stories underground, this Soviet bunker is packed with gas masks and Cold War paraphernalia.

What looks like a suicide in progress is actually a statue of Sigmund Freud.

A bust of Franz Kafka spins in pieces, reflecting the writer's inner torment.

A steampunk-styled three-floor factory churning out art, activism, and electronic beats.

The first museum in the world devoted to sexual gadgetry.

A Jenga-style cylindrical tower of books that appears to go on forever.

Macabre astrological automaton clock dating to the late 1400s.

A church of bones, decorated with 40,000 human skeletons.

The history of occult science is turned into a creepshow at this lurid Prague tourist attraction.

Inhospitable caverns just beneath this island paradise offer insights into alien worlds.