Zwinger

The Zwinger in Goslar is a battery tower that is part of the fortifications of the old imperial city of Goslar, Germany. It is located on the Thomaswall in the south of the town and was built in 1517. On this side Goslar was strongly dominated by the nearby hill of Rammelsberg, which would have made a good location for positioning enemy guns in the event of an attack on the town; the town fortifications therefore needed the extra protection of a strong battery tower at this point.

The stonework of Goslar's Zwinger was predominantly made of sandstone quarried from the Sudmerberg northeast of Goslar and mortared with burnt lime. Because lime burning was still in not fully developed, the builders mixed the mortar with horsehair, quark, goat's milk and ox blood to harden it fully.