St. Bartholomew's Church in Czermna, Poland, is nothing more than a cute historic chapel from the street. The exterior features modest decoration and a charming peaked roof. If you didn't know better, you would probably pass it by without a second glance. However, you'd be missing out.

The church is also known as Kaplica Czaszek, literally translating to "Skull Chapel." That should tip you off as to what you might walk into. Notice the skull and crossbones tucked between the two reclining angels on the building's facade.

The church was built in 1776 by a Czech priest named Vaslav Tomaszek. Apparently, he was familiar with another church in what is now the Czech Republic, because he decided to use the church for two purposes: as a regular church and as a mass grave.

The church is decorated with the bones of more than 3,000 people. They include casualties of the Thirty Years' War (1618 - 1648) and the Silesian Wars (1740 - 1763). It also contains the bones of those who perished in various epidemics of cholera, plague, and syphilis, as well as those who died of starvation. From 1776 to 1804, Tomaszek collected the bones of the dead, cleaned them, and arranged them carefully all over the chapel, completely covering the walls and ceilings with skulls and leg bones.

What was the point of this gruesome project? The church was intended to be a shrine for the dead, and the display of the skulls was meant as an honor to the people who perished from violence and disease. It was also meant to serve as a "memento mori" for the living, reminding them that they, too, would one day die. That doesn't mean that Tomaszek was immune to being interested in the weirder aspects of an already weird project. The altar, seen here, is reserved for the more curious specimens. These skulls include a few deformed by syphilis, the skull of a local mayor, several skulls punctured by bullet holes, and the skull of an alleged giant. Tomaszek's skull joined the crowd when he died in 1804.

The church's main area holds the bones of about 3,000 people, but there's a crypt below that houses about 21,000 more remains.