Bluebeard, The Opera/Catching Up#9

I went to an outdoor opera, called Blauwbaard, performed by Holland Opera.
Bluebeard is the thrilling story of a man with a mystery. During a party around his fort Bluebeard let his eye on Judith. He's courting her, and marries her that same night. Bluebeard gives Judith the keys to his fortress and expressly forbids her to enter his private room. Will she find there the secret about his 7 vanished wives?

It played at Fort Rijnauwen, one of the fortresses of the Dutch Waterline.
The New Dutch Waterline was a military line of defence that extended from the former Zuiderzee near Muiden to the Biesbosch. The Line was established as a protective ring approximately 85 km long and 3-5 km wide around the Dutch cities of Muiden, Utrecht, Vreeswijk and Gorinchem.

The New Dutch Waterline's primary element of defence was water. This was thanks to an ingenious water management system comprising sluices, flood canals, and existing waterways and dikes. A seemingly shallow layer of water, about 40 cm deep, was enough to make the land treacherous and difficult to pass for soldiers, vehicles and horses. At the same time, it was too shallow to navigate by ship. In total, the Waterline could be completely inundated within only three weeks. Weak points along the natural defence line were strengthened with forts, bunkers and group shelters. In addition, the Line included five fortified cities: Muiden, Weesp, Naarden, Gorinchem and Woudrichem.