Great Britain occupied Menorca principally to gain possession of Maó’s deep natural harbour. It built Fort Marlborough to defend the sound and protect Castell San Filipe, which it had also overrun. Most of the fortress is excavated into the rock beside the charming emerald-green inlet, Cala de Sant Esteve (2.5km beyond Es Castell – known historically as Georgetown to the Brits). A short video sets the historical background to a walk through the tunnels, elivened by figurines, explosions and a well-produced recorded commentary (including an English version). From the central hillock there’s a fine view of Cala de Sant Esteve, the scant above-ground remains of Castell San Felipe and, to the south, the circular Torre d’en Penjat (Torre Stuart).