After the big shake of 1755, the new buildings incorporated a set of features intended to supply them with adequate seismic behavior, enabling them to resist horizontal loads and to dissipate a considerable amount of energy. Among these measures the so -called �Gaiola� (the Cage) stands out , unquestionably Gaiola is based on a set of timber members embedded along the inner face of the main stone masonry facade walls.
�Baixa Pombalina �allow us to interpret an outstanding anti-seismic construction system, which was a step beyond its time.