Gola del Bottaccione
A narrow gorge cuts behind Gubbio's northern wall where a Roman aqueduct, a medieval hermitage and one of the most scientifically significant rock faces on Earth share a single dramatic kilometre. The Bottaccione Gorge is where geologists Luis and Walter Alvarez found the iridium-rich clay layer in 1980 that led to the asteroid-impact theory of dinosaur extinction.
The Famous Clay Layer
A small roadside marker indicates the precise stratigraphic boundary between the Cretaceous and Paleogene periods — the K-Pg boundary — visible as a thin rust-red band in the limestone cliff face. It is an almost absurdly understated monument to one of science's great discoveries, and standing in front of it with that context in mind is genuinely moving.
The gorge road (SS298) is open to traffic but lightly used, and the cliffs on either side display 100 million years of ocean sediment compressed into a few hundred metres of exposed rock. Even without a geology background, the sheer scale of deep time becomes viscerally real.
Walking the Gorge
A footpath runs alongside the stream for roughly 3 km from the edge of town to the small Eremo di Sant'Ambrogio, a hermitage chapel carved partly into the cliff face and still occasionally used for quiet retreat. The path is flat, shaded and easy, making it a perfect early-morning or late-afternoon walk when the light is soft and the gorge is cool.
The Roman aqueduct arches visible along the route date to the 1st century AD and fed the baths and fountains of ancient Iguvium. Several sections are remarkably intact and photogenic against the limestone walls and overhanging vegetation.
More of Gubbio
Discover where to stay, what to do and the best deals for your trip.
Explore Gubbio →
