Legend has it that the grotto hidden among the craggy cliffs on San Marco hill in Sutera in the heart of Sicily holds a treasure chest full of gold coins. In order to find it, three men must dream simultaneously about the precise place to dig. Treasure or no treasure, the grotto itself is an archaeological gem, its walls adorned with a multi-coloured Byzantine-esque 16th-century fresco depicting Jesus, the Virgin Mary and Saints Paulinus, Luke, Mark and Matthew.

One of the first mountain oratories in the world, it was built by Basilian monks in the 9th century. But time has weathered the frescoes, which have been completely abandoned to the elements. Anyone who is interested can enter through a flimsy gate as there is no key and chain. But the grotto, now overgrown with vegetation, is unknown even to people living in nearby villages.