The location is the town of Oristano on Sardinia but the cheese is popular throughout Sardinia.
Casu marzu (also called casu modde, casu cundídu, casu fràzigu in Sardinian language, or in Italian formaggio marcio, "rotten cheese") is a traditional Sardinian sheep milk cheese, notable for containing live insect larvae. It is found mainly in Sardinia, Italy.