Terrestrial fortification, built in the middle of the 17th century, designed by the Dutch Jesuit João Paschasio Cosmander, with a bastioned layout, following the main characteristics of the Dutch School, the First Dutch Fortification Method

The walls of Elvas are the largest bastioned fortifications in the world. They have been part of the historical-cultural ensemble inscribed on the UNESCO World Heritage list as "Frontier and Garrison City of Elvas and its Fortifications" since June 30, 2012. The walls began to be built in the reign of Dom Sancho II, having been carried out between the 17th and 19th centuries. They have an area of ​​300 hectares and a perimeter ranging from eight to ten kilometers (4700m), Valença 2600m and Almeida 3000m, Avila 2500m), representing the largest system of bastioned fortifications in the world (represents the largest bulwarked dry-ditch system in the world).