Located in Mellieħa, St. Agatha’s Tower is a large watchtower. It was built between 1647 and 1649. The design of the tower is completely different from the other Lascaris towers, but on the other hand it is similar to the Wignacourt towers. The Saint Agatha Tower is the last large bastioned tower to be built in Malta.

The structure is a square tower with four corner towers. The turrets’ fire hydrants provide interlocking fields of fire that command the base of the walls and the gate, with other large fire hydrants in the faces of the main tower. The outer walls are about four meters thick and the interior of the tower is surrounded by a vaulted roof. The corner turrets are topped with characteristic fishtail battlements. 

The tower is located on the ridge of Marfa Ridge in northwestern Malta, overlooking the natural harbor as well as the potential landing site of Mellieħa Bay, with a beautiful view of Comino and Gozo. It was the main fortress of the Knights in the west of Malta, with a garrison of 30 men, ammunition and provisions to withstand a 40-day siege. 

It continued to have a military function throughout the British period, and was occupied during both world wars. From the British period, it continued its military function by being used as a radar station by the Armed Forces of Malta.

At the end of the twentieth century, St. Agatha’s Tower was in very poor condition. The tower was restored by Din l-Art Ħelwa from 1999 to 2001, with the help of a large industrial sponsorship. As a result, the turrets and siding were replaced, the walls, roof and interior staircase were rebuilt, and the interior walls were painted. Today, the tower is still under the care of Din l-Art Ħelwa and is open to the public.