Stone memorial that's said to predict the death of the pope and the site of the Cadaver Synod.

A Nesting Doll of Churches.

This former Roman Catholic Church still contains the embalmed hearts and organs of 22 popes.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

Architectural monsters are devouring this palace's every door and window.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

A collection of objects supposedly singed by the hands of souls in purgatory.

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

One of several skulls claiming to belong to the beheaded St. John the Baptist is on display at this Roman church.

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

This palatial botanical garden is home to one of the largest pipe organs ever installed in a private residence, and a piece of Wood's cycad.

An extensive collection of ancient Egyptian artifacts and mummies.