In 1993 Lanzarote was given UNESCO biosphere status, and remains the only entire island in the world to hold the honour. A unique volcanic landscape contrasts with widespread development fuelled not only by the lucrative tourist industry but also by a population that has doubled in the last 20 years. Corruption amongst businessmen and politicians has led to illegal hotel developments, which according to recent reports number over a half of all hotels on the island. Politicians have been jailed and UNESCO Reserve status is rumoured to be under threat.