The largest Roman Catholic Church in North America (140m long, 12 000 m2), the basilica was built between 1920 and 1959 in tribute to the Virgin Mary, the Mother of Christ and patron saint of the US. Blending Romanesque and Byzantine styles, it houses a significant collection of contemporary ecclesiastical art, the most striking piece being the gigantic mosaic of Christ. This Marian sanctuary exudes an unusual fervour.