The ESRF physical plant consists of two main buildings: the experiment hall, containing the 844 metre circumference ring and forty tangential beamlines ; and a block of laboratories, preparation suites, and offices connected to the ring by a pedestrian bridge. The linear accelerator electron gun and smaller booster ring used to bring the beam to an operating energy of 6 GeV are constructed within the main ring. Until recently bicycles were provided for use indoors in the ring's circumferential corridor. Unfortunately they have been removed after some minor accidents. But even before this it was not possible to cycle continuously all the way around, since some of the beamlines exit the hall.