Alcobaça Monastery is a Roman Catholic church in the city of Alcobaça, in the Oeste subregion. Itineraries to experience the monastery of Alcobaca. Mosteiro de Alcobaça is an imposing and magnificent monastery complex and one of the most beautiful examples of early Gothic architecture in Portugal. Alcobaça Monastery (Mosteiro de Santa Maria de Alcobaça) is Portugal's largest church and monastery and is a UNESCO World Heritage Site. Alcobaça, a small town in central Portugal, is dominated by the monastery where Pedro and Inês came to rest, but has more to offer.