Leaving Es Mercadal in the direction of Ciutadella, there is a large watercistern built in 1735 by order of the English governor Richard Kane, during the British rule. This reservoir collects rainwater to supply the troops midway between Maó and Ciutadella. It measures 20 by 40 meters and 9 meters high, with massive, sloping walls typical of fortifications of the era, indicating a military engineering design.
Today, the inhabitants of Mercadal still benefit from its high-quality water.