How Was Civita di Bagnoregio Built

Civita is built of tufa quarried from directly beneath it, which is why the town and the cliff read as one object. The stone is soft enough to cut with hand tools and hardens on exposure, so cellars, stables and storerooms were excavated into the rock below the houses rather than built.

The Etruscans were the first to work it that way. Their drainage tunnels under the ridge were designed to take water off the tufa before it reached the clay — the correct engineering response to this geology — and their neglect over centuries is part of why the erosion accelerated.

The Porta Santa Maria is the only surviving gate of five, a tunnel cut through the rock with medieval masonry above an Etruscan cutting. The main street beyond it runs the length of the outcrop to a square, with the church of San Donato on a site used for worship since the Etruscan period.

The modern layer is the bridge and the stabilisation: the 1965 span replaced a succession of earlier crossings, and the cliff face now carries injected grouting, anchors and drainage. What holds Civita up is no longer only geology.