Grutas de Mira de Aire

Portugal’s largest cave system, 14km southeast of Porto de Mós, is very commercial and old-fashioned, although the caves themselves are impressive. The 45-minute tour's spiralling 110m descent leads through psychedelically lit chambers to a final cavern containing a lake with a rather hokey fountain display. There's also a children's zoo and an aquapark here. There are three Rodotejo buses weekdays from Porto de Mós (€2.65, 35 minutes).