The current tower of Sant Nicolau stands on the same spot where an older medieval tower once existed, taking its name from a nearby chapel dedicated to Saint Nicholas, demolished in 1799. This tower was built in the late 17th century to protect the entrance to the port and nearby coves of Ciutadella, preventing enemy ships from landing. The preserved plans were created by military engineers Josep Castellón in 1680 and Blas Zappino in 1872, although the tower has undergone several modifications over time to adapt to the artillery requirements of each period. It ceased to have a defensive role in the 19th century. Recent restorations have restored the structure to its original appearance.
It is open to the public during the tourist season, and visitors can enjoy breathtaking sunsets from the gun terrace.