Walk through a restaurant's refrigerator door to reach this hidden bar.

This colorful but controversial ceiling has been likened to a 21st-century Sistine Chapel.

Where Mary Shelley’s "Frankenstein" and John William Polidori's "The Vampyre" were born.

Isaac Newton's former home, where the famous apple tree still stands.

The top of society once luxuriated in this world-class hotel, which continues to impress, even in ruin.

These beautiful ruins deep in the Pennsylvania woods are thought to have been a ski lodge or a speakeasy, but no one really knows.

This architecturally eclectic fortress witnessed centuries of bloody turmoil, including the massacre of its ruling clan.

The decaying remains of a once-luxurious Soviet spa town.

This neon lit Georgian cave claims to hold the boulder Prometheus was chained to.

Underground monastery and fortress.

Take respite inside this jaw-dropping church while climbing the volcano where Georgia's Prometheus was once chained.

According to legend, this cavern holds the passage that Persephone used to travel to and from the underworld.

A cave dwelling that was started by the Celts, expanded by monks, and finished by knights.

An eerie, protected forest of old-growth oak trees, many of which are now dead.

An Aztec temple, the largest man-made pyramid in the world, sits buried in earth with a Spanish church set on top.

High atop a Mexican rainforest mountain, this ancient pyramid once drew pilgrims countries away.

Every equinox this Maya pyramid puts on a spooky ancient light show.

The most complete statue of this Aztec god sits a top a throne carved with images of hallucinogenic plants.

The ruins of the bathhouse used by the ill-fated last Aztec emperor still lie in Chapultepec Park.

An indigenous take on European design creates a stunning visual overload.

The ruins of an ancient Mayan city, beautifully preserved and only accessible by boat.

A 500-year-old series of tunnels long believed to be folkloric was uncovered beneath the streets of Puebla.

These colonial murals are a fascinating hybrid of Spanish and Indigenous aesthetics.

The former home of the hard partying literary power couple is now one of the only museums devoted to their story.