The Capuchin Crypt is a small space comprising several tiny chapels located beneath the church of Santa Maria della Concezione dei Cappuccini on the Via Veneto near Piazza Barberini in Rome, Italy. It contains the skeletal remains of 4,000 bodies believed to be Capuchin friars buried by their order. The Catholic order insists that the display is not meant to be macabre, but a silent reminder of the swift passage of life on Earth and our own mortality.
https://en.wikipedia.org/wiki/Capuchin_Crypt