They are small grottos cut in the rock.
At Syracuse also there are very extensive catacombs known as " the Grottos of St John."
The cathedral, of the 12th century, has a carved portal and three apses decorated with small arches and pilasters, and contains a fine pulpit and episcopal throne in marble mosaic. Near it are two grottos 1 To the period after 335 belong numerous silver and bronze coins with the legend Caleno.
Here are the temples of Debfld, the temple and quarries of Kertassi, the temples of Kalabsha, Bet el Wali, Dendr, Gerf Husn, Dakka, Maharaka, Es-Seba, Amgda and Derr, the grottos of Elles ya, the tombs of Aniba, the temple of Ibrim, the great rock-temples of Abu-Simbel, the temples at Jebel Adda and Wadi Halfa, the forts and temples of Semna, the temples of Amgra (Meroitic) and Soleb.
Amongst the best-known are the grottos of Adelsberg, the larger ones of Planina and the Kreuzberghohle near Laas.