The Chapel of Sao Pedro de Penaferrim sits just outside the walls of the Moorish Castle in Sintra. The chapel was built in the late 12th century. In the past, the area outside the inner walls was as a burial ground for the the Muslims and then later for the Christians.
Now, there is a glass cover placed above the burial grounds of the castle. Under the glass, a skeleton was placed inside a shallow grave to show how people had been buried there in the past. After the collection of all bones, they were brought to a mass grave and deposited there (few meters away from this site).