HWW

Church Wall,
Mértola is a town and municipality in southeastern Portuguese Alentejo near the Spanish border. In 2011, the population was 7,274, in an area of approximately 1,292.87 square kilometres : it is the sixth-largest municipality in Portugal. Meanwhile, it is the second-lowest population centre by density with approximately 5.62 persons/1 square kilometre (second to the adjacent Alcoutim).
The seat of the municipality is the town of Mértola, which has around 2800 inhabitants (2011), located on a hill over the Guadiana River. Its strategic location made it an important fluvial commercial port in Classical Antiquity, through the period of Umayyad conquest of Hispania: Mértola's main church (the Church of Nossa Senhora da Anunciação) was the only medieval mosque to have survived the period in Portugal, it is part of the church.