This monastic complex, one of the most important monuments in Matera, comprises dozens of chambers carved into the tufa limestone over two floors. Chiesa di Madonna delle Virtù was built in the 10th or 11th century and restored in the 17th century. Above it, the simple Chiesa di San Nicola del Greci is rich in frescoes. The complex was used in 1213 by Benedictine monks of Palestinian origin. The churches are sometimes used for art installations (admission charges apply).