Church of San Bernardino alle Ossa

San Bernardino alle Ossa is a church in Milan, northern Italy, best known for its ossuary, a small side chapel decorated with numerous human skulls and bones.

In 1210, when an adjacent cemetery ran out of space, a room was built to hold bones. A church was attached in 1269. Renovated in 1679, it was destroyed by a fire in 1712. A new bigger church was then attached to the older one and dedicated to Saint Bernardino of Siena.

Source: Wikipedia