This is a book of delights. A volcanologist and two geologists unpick the fabric of Rome, from its roots of silts and gravels overlain by volcanic flows to the summits of the seven hills. Lava from volcanoes in the neighbouring Alban Hills made a useful building material, soft enough to cut with a knife yet hardening into a tough stone when exposed to air. The place is shaped by fire and water – and rubbish: the site has been inhabited for so long that the layer of debris stretches 65 metres deep. It has become part of the geology.
The Seven…
