The Garrison Border Town of Elvas and its Fortifications is a Unesco World Heritage Site, inscribed in the World Heritage list in 2012. Elvas is a Portuguese city in Alentejo, near the Portuguese-Spanish border.The site, extensively fortified from the 17th to 19th centuries, represents the largest bulwarked dry ditch system in the world. Within its walls, the town contains barracks and other military buildings as well as churches and monasteries. While Elvas contains remains dating back to the 10th century, its fortification began during the Portuguese Restoration War. The fortifications designed by Dutch Jesuit Padre João Piscásio Cosmander represent the best surviving example of the Dutch school of fortifications anywhere. The site also contains the Amoreira Aqueduct, built to enable the stronghold to withstand lengthy sieges.