Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

This dramatic rail curve was once the target of a failed Nazi attack.

Memorializing an American tragedy of massive proportions.

Steepest flood safety railway in the entire world.

Frank Lloyd Wright’s most iconic home dangles over a Pennsylvania waterfall.

This Pennsylvania cave holds evidence of the oldest known inhabitants of North America.

The largest university building in the West is a gothic masterpiece containing dozens of theme rooms based on different countries.

A formerly glacier-tipped volcano that inspired none other than Jules Verne.

Breathtakingly blue walls shimmer inside the "Glacier Behind the Town."

Go inside to really appreciate this 500-year-old technological masterpiece.

Macabre astrological automaton clock dating to the late 1400s.

An architect's childhood fantasy treehouse made real.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

An abandoned stretch of highway, deteriorating next to the operational one.

One of the steepest streets in the United States makes an intriguing challenge for cyclists.

A take-out restaurant that only serves cuisine from countries with which the United States is in conflict.