Originally Romanesque, Mariazell's basilica underwent a Gothic conversion in the 14th century, followed by a massive baroque facelift in the 17th century. The result is a strange clash of styles, with the original Gothic steeple bursting like a wayward skeletal limb from between two baroque onion domes. Inside, Gothic ribbing combines with baroque frescoes and lavish stuccowork, while in the upper galleries there's a quite interesting Schatzkammer, which contains votive offerings spanning six centuries, mainly naive-style paintings.
Unusually, the church is centred on a small but exquisite chapel, known as the Gnadenkapelle (Chapel of Grace). This gold and silver edifice houses the Romanesque statue of the Madonna, whose healing powers reputedly helped King Louis of Hungary defeat the Turks in 1377. Except for two days each year, she's dressed up rather doll-like in her Liebfrauenkleid (dress of Our Lady). Both Johann Bernhard Fischer von Erlach and his son Josef Emmanuel had a hand in the baroque interior features; the crucifixion group sculpture (1715) on the high altar is by Lorenzo Mattielli.