In Matera, the two Matera rupestrian churches of Santa Lucia alle Malve, excavated in the Sasso Caveoso, and San Pietro Barisano, located in the Sasso Barisano, are sites of great historical and artistic interest. Both are characterised by extremely interesting painted and sculpted decorations, but are unfortunately subject to the peculiar conservation problems that they share with other hypogean and semi-hypogean sites in Matera.