The Merro well

The Macchia di Gattaceca Nature Reserve spreads over the hilly area between the Tiber valley and the Monti Cornicolani, full of suggestive olive groves, oak woods and meadows. Even though the area has been partially built upon, the estate preserves extraordinary natural treasures: the area’s karst soil has in fact allowed the formation of a giant doline, a natural funnel into the calcareous rock, 30 metres wide at the mouth and 50 metres deep going down to the lake-level. The cavity is actually wider and recalls the Yucatan open-air caves. Underwater, the depth of the doline is at least 392 metres. The visit is made even more fascinating by the impressive thicket of Holm oaks which entirely cover the sides of the doline.

Leave the town of Mentana by car (approximately 5 km) and follow the Strada Provinciale (by road) towards Palombara Sabina and Guidonia until you pass a stretch of the old Roman via Nomentana and cross the Autostrada del Sole motorway, then turn left and follow the signs for the residential area of Selva, where you can park your car and take the narrow asphalt road on the right.

Proceed straight on uphill to the fence with the signs for the Macchia di Gattaceca Nature Reserve. The protected area includes two sections located between the Tiber Valley and the monti Lucretili hills, and is largely cultivated with olive groves and forage plants. After a few minutes you will pass by a fence and cross some meadows to the Merro well, from where the rocky edge of the doline covered with vegetation can be admired. Return to the fence and on the right take the path that descends to the bottom of the well, which is approximately 50 metres deep. The itinerary goes through a thicket of Holm oaks and is fairly steep, with some steps and stretches that can be muddy after rain, and ends with a metal ladder leading to the bottom of the well.

Time 1-2 hours
Marked itinerary Sign posts
Difficulty Easy

For further information, contact:
www.parks.it, www.parchilazio.it
Riserva Regionale di Gattaceca e Macchia del Barco, tel. +39 06 67663301
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Area
Via Nomentana e Via Salaria