Displayed in a glittering brass-and-glass case in the north transept, the shrivelled head of St Oliver Plunkett (1629–81) is this church's main draw (the rest of the martyr was separated at his hanging in 1681). Actually it's two churches in one: the first, a classical style, designed by Francis Johnston in 1791, and the newer late 19th-century Neogothic addition. Opening hours can vary.
