Cripta Arqueológica do Castelo.

Located beneath the floors of the former Convent of Nossa Senhora de Aracaeli, this underground crypt reveals a dense, 2,700-year timeline of human settlement. Unlike traditional galleries, the space functions as a literal excavation site where visitors walk through subterranean layers of history. The chronological route uncovers Iron Age housing, Roman fish-salting tanks, and Islamic cisterns, culminating in medieval Christian fortifications. The architecture is a physical cross-section of Alcácer do Sal’s past, where 12th-century walls are built directly atop Roman and Phoenician foundations. With its low lighting and hushed, atmospheric environment, the museum provides a tactile, silent encounter with the civilizations that have occupied this strategic hillside since the 7th century BC.