A cyclone is a huge storm formed over bodies of water characterized by low pressure and high winds that spins in a circular motion. The 1991 Bangladesh cyclone was one of the deadliest on record, killing 138,000 people and leaving 10 million homeless with winds up to 250 km/h. Cyclones can cause widespread destruction by damaging boats, homes, cars and infrastructure while also resulting in flooding, disease and contaminated water supplies.