A Bibliophile's Dream.

A speakeasy takes on Chicago's drinking culture.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

A lush green oasis in the middle of Chicago.

This morbid, delightful curiosity shop offers everything from animal bones to human teeth.

This whimsical Oz-themed park had a wonderful impact on the surrounding neighborhood.

A monument to the art of slicing people open.

A synth musician's paradise at the heart of a community responsible for the soundtrack to 'Stranger Things.'

Remains of the lost church hide beneath this Spanish Parliament building.

This sweet-toothed bear searching for snacks has been a symbol of Madrid for decades.

Artist Natividad Sánchez wrote a new ending for one of Roman mythology's tragic love stories.

Picturesque intersection of witchcraft and ancient Christianity.

A magnificent waterfall is also home to the remains of a Roman hydraulic engineering system.

This ancient Roman prison is decorated with an upside-down cross not as blasphemy but as saintly tribute.

One of seven Jewish catacombs in Rome and one of only two open to the public.

Installed in an act of one-upsmanship, the annual sundial in this church is also a symbolic victory for the Gregorian calendar.

One of the most important yet well-hidden museums dedicated to the history of medicine.

These distorting, funhouse mirrors achieved fame in a renowned piece of Spanish theater.

Nicknamed the "Spirit of Paul Klee," this colorful apartment building features an array of multicolored panels.

This Art Nouveau gate still stands at the former entrance of a 20th-century Spanish writer's colony.

A statue commemorating a beloved stray dog who was adopted by the entire neighborhood where he lived.

A pair of gigantic baby heads greet passengers at Atocha Station.

Strange masks and obscure costumes are housed in this old Madrid corrala.

A towering monument in Spain has proven to be more labor-intensive than initially planned.