The huge sinkhole that appeared on the Avenidas in Palma on Tuesday morning has exposed the remains of a bastion that was part of the wall built from 1576.
This was the third walled ring around the city and it was built in response to risks of attack by the Ottomans. The bastions, which were where the cannons were placed, were located along the wall that much later acted as a guide for the layout of the Avenidas.
Historian Gasper Valero explains that the existence of the bastions and the wall is well known. "Along all the Avenidas, in the subsoil, are the remains of the wall." In 1912 the walls were demolished, leaving the lower trenches and walls buried.
This was the last of three walls that were built. There is uncertainty as to the first. It could have been Roman or Byzantine. Into the eleventh century, the Muslims built the second wall.