Whether or not they're still inhabited by people who have chosen a meaningful life of service, convents have a calming atmosphere to them. Swing by Capuchos Convent and soak up a bit of spirituality.
This community of nuns is in Caparica, a place that has so much going for it! Belém Tower, Jerónimos Monastery, and Cristo Rei are other worthwhile sightseeing choices not far away when you've finished up at Capuchos Convent.