Cripta Arqueológica do Castelo de Alcácer do Sal

Regarded as the largest archaeological crypt in the country, lies beneath the Castle of Alcácer salt, transformed into the Pousada d. Afonso II. Shows traces of iron age dating back to the 6th century BC, as well as structures of the Roman period and the Islamic occupation, covering a considerable area. Met also medieval Christian-era walls pós-reconquista, based partly on Roman walls which, in turn, overlap the preexisting structures, dating from the iron age.