Volcan Villarrica, Chile

Villarrica is one of the most active volcanoes on the planet, and the sulphurous gases it gives off are a constant reminder that its crater contains a lake of boiling lava. Each of its most recent eruptions - in 1964, 1971 and 1984 - killed about thirty people. Those coming may be deadlier, for more and more tourists come to ski down its slopes. However, the regional emergency bureau keeps a close watch on the volcano's activity, and the slightest explosion - accompanied by a dark plume of smoke - triggers an alert. Skiers are then advised to leave the pistes, while local residents begin carrying out their prepared evacuation plans. Over the last thirty years, Chile, which has 2,085 volcanoes and frequent earthquakes, has perfected an efficient means of dealing with natural disasters, thanks to the advice of international experts (from bodies such as the World Bank and the UNDP), and to close collaboration with other South American countries. Together, the latter have succeeded in reducing deaths from such events by two thirds.