La Xanga is a half-moon shaped cove near the Sa Sal Rossa tower which, in Phoenician and Roman times, and subsequently in the Christian era, was an important commercial hub, with flourishing industries such as preserving and salting fish, fishing, and extraction of the raw material for making purple dye.
Vestiges of these salting and fishing activities still remain, such as part of the open precinct where the tuna caught at the almadraba (place for trapping and catching fish) was unloaded, along with the salt, which was used to preserve the fish, brought from the nearby salt pans. Another witness to this past industry was the huge cisterns that you can still see in the vicinity, near the edge of a steep path.
Elongated arched structures, these cisterns were designed to store fresh water needed for the different activities. Like the rest of the infrastructure in this area, the cisterns were built in the 16th century coinciding with the ambitious and imposing task of building the walls of Ibiza. The cisterns are situated near the open square, just a few metres from the sea, partially sunken into the rocky terrain, with two tanks separated at a distance of about 3 metres. The largest one is over 13 metres long, with the smallest measuring about 8 metres and both about 4.5 metres wide; they are interconnected giving them considerable storage capacity.