The Cathedral Basilica of St Bavo is Haarlem's major Catholic landmark, distinct from the older Grote Kerk in the central market square. Its eclectic architecture mixes neo-Gothic, Romanesque, and other revival styles into a building that feels ambitious, layered, and slightly unexpected.
Inside, look for stained glass, decorative detail, and the sense of a church built to make a statement in a largely Protestant urban landscape. It is a rewarding detour west of the old centre, especially for architecture-minded visitors.