The Meson Experiment area at the Fermi National Accelerator Laboratory (Fermilab) outside Chicago, Illinois. Protons accelerated in Fermilab's giant Tevatron accelerator are deflected from their orbital paths into a switchyard, where a number of separate beams are produced to serve three experimental areas. The beam for the Meson area comes down a tunnel under the raised bank leading to the red- roofed building. The protons smash into a target to produce secondary beams of mesons: pions & kaons. These particles are studied in 12 or more experiments housed in the main experiment building & the metal tunnels extending from it.