The Abbey can be visited
Ziesar Abbey

The Ziesar Monastery was a monastery in the episcopal city of Ziesar. The episcopal city of Ziesar successively housed 2 monasteries within its walls.
Franciscans+
Around 1226, Franciscan monks first settled in Ziesar, but as early as 1271, they moved their monastery to Brandenburg an der Havel. They also transferred the remains of their founder, Magister Helyas, who died in 1237 and was buried in St. Crucis in Ziesar, to their new monastery.
Cistercian Nuns+
Around 1330, supported by Bishop Ludwig, the first Cistercian nuns settled in the still-preserved monastery building next to the city church of St. Crucis. This church was also used by the nuns as their monastery church. A passage was built from the monastery building to the church. There, the nuns could directly access their own gallery.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: Gottfried Hoffmann
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 52.2668, 12.2870