These 13th-century gravestones are dedicated to the first university teachers. They used to write down "glosses" into their documents.
Wikipedia https://it.wikipedia.org/wiki/Tombe_dei_Glossatori_della_Scuola_bolognese
Address 6/A Piazza Malpighi, Bologna 40123, Italy
Coordinates 44°29'40.752" N 11°20'10.885" E