Completed in 1829 under the supervision of James O'Donnell, the Gothic Revival basilica is especially renowned for its magnificent interior. The opulent decor, designed by Victor Bourgeau, features sculptures, wainscoting and giltwork typical of provincial religious architecture. The main nave, lined on both sides by deep-set double galleries, measures 68m/223ft long, 21m/69ft wide and 25m/82ft high. As visitors enter, eyes are drawn to the ensemble of white oak statues, part of the imposing reredos that stands out against the background's soft blue hues.