The size of our simulated landslides reflects the amount of disintegrated material available for sliding, which is controlled by the peak strength of the slope material and to a lesser degree by the pre-failure slope angle. The observed size of natural landslides, therefore, reflects mainly the local natural material strengths. We hypothesize that the observed global characteristic landslide size is a result of the limited thickness (generally up to a few meters) of disintegrated and weathered material that exists on hill slopes, poised and ready for sliding.