The Abisso Ancona, the first chamber on the route, is big enough to hold Milan Cathedral: 180 metres by 120 at the base, 200 high, more than two million cubic metres of empty space. When Rolando Silvestri, of the Marche caving group of the Ancona CAI, found the way in on 25 September 1971, a hole the size of a car steering wheel opened on the north flank of monte Valmontagnana at 450 metres, nobody suspected the scale of it: the depth was estimated by dropping a stone and timing the fall, and the first calculation gave more than 125 metres.
What to see
The made-up route crosses the Abisso Ancona on suspended walkways, then the Sala 200, a corridor exactly as long as its name says, with the Obelisco at its centre, a stalagmite of fifteen metres, and the Sala delle Candeline, where thousands of small cylindrical stalagmites rise from a ring of rock like candles on a saucer. Then come the Sala Bianca, sheathed in pure calcite, and the Sala dell'Infinito, so called because the first explorers went round it several times before finding the way out.
The names of the formations were invented by the cavers and stuck: the Spada di Damocle, the thickest stalactite, 7.40 metres long and 150 centimetres across; the Fetta di pancetta, pink, and the Fetta di lardo, dead white; the Canne d'organo, blades that ring when struck; the Castello delle streghe. All of it grew inside limestone laid down over 190 million years and hollowed out about a million years ago, when the cold water of the Sentino met sulphurous water rising from below and multiplied its power to dissolve rock. Not a ray of daylight reaches inside: the lighting is artificial and cold white, chosen so as not to feed algae on the formations.
Visiting
Entry is only with a guide, in groups, through the artificial tunnel dug after the survey work of the engineer Aldo Neroni Mercati of Fabriano, remembered by a plaque at the door; the caves have been run since 1972 by the Consorzio Frasassi and open to the public since 1 September 1974, with more than twelve million visits in that time. You arrive at San Vittore di Genga, on the Rome-Ancona railway, and a shuttle runs from the ticket office to the entrance. Inside it is a steady 14 degrees with humidity close to 100%: bring a jacket and closed shoes, as the path climbs and is slippery. The tour lasts a little over an hour; on request there are also caving routes with helmet and overalls.
Our editors' tip
We book the first slot of the morning, when the group is small and the guides have time for questions, and we hang back at the end of the line: from there you hear the dripping and the silence better. Afterwards, instead of driving straight off, we walk up the gorge to the Tempietto del Valadier, of 1828, and to the sanctuary of Santa Maria infra Saxa, recorded from 1029 and wedged under the rock: half an hour on foot and the day changes shape. One story we always tell: in 1986 the sociologist Maurizio Montalbini spent 210 days down here for an experiment on biological rhythms, and came out convinced that only seventy-nine had gone by.
