The Anglican cathedral was built between 1628 and 1633 in the Gothic style and during the 1689 siege, its steeple housed an artillery weapon. A cannon ball is kept under the porch in memory of this event. Added in 1910, the chapter hall contains a small museum exhibiting historic memorabilia, including some huge padlocks from the city's old gates. Also look out for the carved heads of the bishops of Derry in the nave.