------------- A part of the code where efficiency, accuracy, consistency and flexibility have combined giving very effective results is the FLUKA geometry. Derived from the Combinatorial Geometry package, it has been entirely rewritten. A completely new, fast tracking strategy has been developed, with special attention to charged particle transport, especially in magnetic fields. New bodies have been introduced, resulting in increased rounding accuracy, speed and even easier input preparation. * Combinatorial Geometry (CG) from MORSE [Emm75], with additional bodies (infinite circular and elliptical cylinder parallel to X,Y,Z axis, generic plane, planes perpendicular to the axes, generic quadrics). * Possibility to use body and region names instead of numbers. * Possibility of using body combinations inside nested parentheses. * Geometry directives for body expansions and roto-translation transformations. * Distance to nearest boundary taken into account for improved performance. * Accurate treatment of boundary crossing with multiple scattering and magnetic or electric fields. * The maximum number of regions (without recompiling the code) is 10000. * The tracking strategy has been substantially changed with respect to the original CG package. Speed has been improved and interplay with charged particle transport (multiple scattering, magnetic and electric field transport) has been properly set. * A limited repetition capability (lattice capability) is available. This allows to avoid describing repetitive structures in all details. Only one single module has to be described and then can be repeated as many times as needed. This repetition does not occur at input stage but is hard-wired into the geometry package, namely repeated regions are not set up in memory, but the given symmetry is exploited at tracking time using the minimum amount of bodies/regions required. This allows in principle to describe geometries with even tens of thousands regions (e.g. spaghetti calorimeters) with a reasonable number of region and body definitions. * Voxel geometry is available on option, completely integrated into CG. Special options: * Geometry debugger. * Plotting of selected sections of the geometry, based on the Ispra PLOTGEOM program. * Pseudoparticle RAY to scan the geometry in a given direction.