An overview shall be presented of FLUKA, a general-purpose code for the Monte Carlo simulation of radiation transport, and of its powerful graphical interface Flair. FLUKA can transport over 60 particle species, including photons, leptons, hadrons and ions, at energies up to the PeV domain and down to the keV domain, with the exception of neutrons, which can be transported down to the meV. Material geometries can be described via FLUKA's combinatorial geometry package, from the simplest geometries up to elaborate geometries e.g. extended portions of the Large Hadron Collider. FLUKA accounts for the most relevant electromagnetic and hadronic interaction mechanisms, providing a self-contained approach to the simulation of coupled hadronic and electromagnetic radiation showers. FLUKA's graphical user interface Flair provides a fully integrated environment to run FLUKA, from the preparation of the input file, to the construction of the geometry, specification of the radiation source, of the quantities to be scored. Furthermore, it controls the execution of the simulation, the processing of output files, and the visualization of simulation results. To showcase the
capabilities of Flair and FLUKA, several application examples shall be presented, ranging from neutronics to medical physics.