St Patrick's, the Catholic cathedral, is one of the most ambitious Gothic Revival churches in Australia — a long, high, austere bluestone building with a 78-metre spire visible from across the basin. It was begun in 1858 to serve the Irish-Catholic mining population (a large share of the diggers were Irish) and finished, after multiple stalls, in 1939.
The interior is comparatively plain — there were not enough donations in the 1930s to finish the planned decoration — but the proportions are remarkable. The acoustics are very good and the cathedral hosts a regular concert series. Open daily; Mass times posted at the door.