The Schlosskirche St. Michael is Pforzheim's oldest building — a Romanesque–Gothic former collegiate church on the rocky bluff above the Enz. Most of the city around it was flattened in 1945, but enough of the church survived to allow reconstruction, and the result is a strange and powerful mixture of medieval stone and post-war restoration.
Inside, look for the Renaissance tomb monuments of the Baden-Durlach line in the choir, and the simple memorial slab to Johannes Reuchlin (1455–1522), the Hebrew scholar and humanist born in Pforzheim. Open daily; free.