This video stream shows live images of particles as they zip through a cloud chamber which is set up in the public Microcosm exhibition at CERN. Different shapes of clouds are formed depending on the particle type, energy and direction. The clouds are the result of particles interacting with the vapour inside the chamber. Most particle tracks are caused by natural radioactivity (present in the soil and air) and particle showers originating from the Earth's atmosphere. These showers are created by cosmic particles hitting the Earth's atmosphere, which transforms them into myriads of lower-energy particles like pions, muons and electrons. This live stream is available during the opening hours of the Microcosm exhibition at CERN. In general, the stream should be running from Monday to Saturday, 8:30 - 20:00 (Swiss time).