Monastery of San Nicolò l'Arena, Benedictine monastery in Nicolosi, Italy.

Monastery of San Nicolò l'Arena is a Benedictine structure in Nicolosi featuring a small portico decorated with frescos and architectural elements crafted from local lava stone and white stone. The complex was constructed using materials sourced from the volcanic deposits of the region.

In 1150 Simone del Vasto donated the rural church of San Nicolò l'Arena at Nicolosi, with its hospice, vineyards and pastures, to a community of monks; in 1156 Countess Adelasia turned it into a monastery in the Ruvolo Grosso district. In the 14th century Frederick III of Sicily made it the head house of the cenobites, and the monks' devotion to St Nicholas of Bari plus the red volcanic sand (Latin arena) gave it the name San Nicolò la Rena. In 1483 it joined the Benedictine congregation of Sicily, and in 1537 the monks moved to Catania.

The name Nicolosi probably derives from the monastery, and "l'Arena" comes from the Sicilian "a rina", the red volcanic sand of the area. The monks venerated San Nicola di Bari, and the complex held the relic of the Santo Chiodo, the Holy Nail of the Cross, much revered by the people of Catania. Since March 2005 the restored monastery has housed the regional authority of Etna Park.

The monastery stands near Nicolosi on Etna's southern slope, roughly 15 km from Catania; the usual approach is the SP92 road up from the city, not the A19. Since March 2005 the restored complex has housed the headquarters of the Parco dell'Etna regional authority, so parts of the building serve administrative rather than monastic use.

The name Nicolosi likely derives from the monastery, not the reverse. "Arena" comes from the Sicilian "a rina", meaning sand, and refers to the red volcanic sand of the area. In 1537 the monastery hosted Benedetto Fontanini, who probably wrote the Beneficio di Cristo here. Since March 2005 the restored complex has housed the regional Etna Park authority.