The Sinopie Museum in Pisa is located in Piazza dei Miracoli, in the ex-Spedale della Misericordia. The building was designed in the 13th century by Giovanni di Simone, the architect that built the Leaning Tower, and was established as a shelter for pilgrims. Today it is part of the Hospital of Santa Chiara. The Museum is dedicated to sinopie, or fresco preparatory drawings, which are quite useful for art historians because they help scholars distinguish between the various artists who collaborated on a work of art. A majority of the drawings come from the Camposanto in Pisa, which suffered a terrible fire in 1944 when bombs were dropped on the site during World War II: to save the 14th-century frescoes, it was decided to detach them from the walls and place them on panels, and it was during this delicate procedure that numerous preparatory sketches came to light.