The karstic complex of Onferno is considered to be among the most important in Italy both because of the caves and the chalk. It unwinds beneath the castle and parish, and originates from the erosive action of a little underground torrent, which about fifty to one hundred thousand years ago excavated its course in the dephts of the great mass on which the "Castrum Inferni" rose. It is made of grey selenite chalk from the Inferior Messianic period (5-6 million years ago), transported to Onferno a long long time ago, during some movements of the Earth's crust. In this mass the ever active river has created deeply grooved meanders, great underground rooms and long pieces of hanging chalk, which stick out, in the vaults, in various shapes. Today only a small stream of the old river remains, which runs to the right and the left of the course, fed by two courses, which start in the sala of Mammelloni (the Knoll Room). The first naturalist who attempted scientific exploration of the caves was Ludovic Quarina in 1916.
A warning regards clothing: the cave has an average temperature of 12-14 degrees therefore we advise you to avoid too summery clothes and to take a light jacket with you, comfortable shoes too and rubber soles, considering that the course has been maintained as "natural" as possible and humidity often makes the route slippery.
From November guided tours every Sunday at 11.30 am, 3.00 pm and 4.30 pm
Access to the caves could be temporarily suspended during the year related to the protection of wildlife, maintenance or temporary unavailability of routes.
meeting room with facilities
Not accessible to disabled guests.
how to get there:
bus line n. 172
bus network and timetable
from Rimini take provincial road: SP 31 to Coriano and then provincial road SP 18 to Gemmano
rates of entry include entrance to the Oriented Nature Reserve, Visitors’ Centre and Museum
Opening hoursOpening period: open all year round
Entrance: fee payable