Considered virtually impregnable when first built some 2,000 years ago, the Citadel of Bam— now close to Iran's border with Pakistan — was a military garrison that commanded important trade routes, notably the Silk Route. The modern city, wrecked by a devastating earthquake in 2003, lies to its southwest. The chiefly mud-built citadel was also largely destroyed within seconds of the cataclysm. It had been divided into quarters, walled around and watched over by guards' housed in 38 towers. On the southern side there were four ramparts, and to the northeast, another colossal rampart. The citadel had largely been rebuilt by the Safavid dynasty between 1502 and 1722, so inside its protective earthwork rings Was a remarkably civilized, well-serviced city not quite Isfahan, perhaps, yet complete with two-storey houses, many with private baths, together with a palace, shops, bazzar, caravanserai, mosques, military base, public baths, and gymnasium.