1. Device for monitoring a spatial volume ( 10 ), comprising a plurality of cameras, whereby the cameras are disposed in pairs, with reference to the spatial volume ( 10 ) to be monitored, in such a manner that a three-dimensional spatial image can be produced by means of superimposing the camera images ( 34 , 34 ′) of a camera pair ( 11 , 11 ′), in each instance, wherein at least two camera pairs ( 11 , 11 ′) jointly cover a spatial volume ( 10 ), in such a manner that at least two three-dimensional spatial images of the same spatial volume ( 10 ) can be produced, from different spatial directions.