Military outdoor museum Smečno, at the western wall of the castle park, Smečno, Kladno District. View of the reconstructed blockhouse made of reinforced concrete (A-3/41/B2-80 Z light pillbox), model 37, B2 - an object of prewar Czechoslovak line of light fortifications around Prague (VOP) - built in 1937. One of several such objects, which have been preserved.