Caerwent grew up inside the walls of Venta Silurum, the Roman market town of the Silures. Long stretches of the town wall still stand — among the best-preserved Roman town defences in Britain — and you can follow them round the edge of the present village, along with the marked-out foundations of shops and a temple. Free to visit; Caldicot station is about 3km south.

© Michael Dibb / Geograph · CC BY-SA 2.0