Magnificent «end of the world», Bonifacio has both a harbour and a upper town. The marina, a port constructed at the bottom of a 1,500 metre fjord, is a safe haven for boats, closed off by a narrow bottleneck and protected from high tides by a 60-metre high promontory. The upper town, perched on the cliff edge, with its old houses linked by flying buttresses which are actually gutters that direct rainwater into water tanks.