Drones (unarmed aerial vehicles, or remotely piloted aircraft) crash at an alarming rate. Disarmingman has created a database of crashes of large drones around the world.
Drones are increasingly touted as solutions for a wide variety of surveillance and monitoring problems and the number of drones in the world is proliferating wildly. Pressure is increasing to have drones licensed to fly in airspace over populated regions, so that drones can be used for such prosaic purposes as traffic monitoring. The Drones Crash Database makes sobering reading.