The Crystal Valley was an area on the planet Monastery where large crystal spires would grow from the ground at dangerous speeds. The valley was to be the site where Luke Skywalker and Darth Vader had a lightsaber duel, and was chosen by Domina Tagge because she wanted to ensure that both combatants were killed. However, Vader substituted Baron Orman Tagge in place of himself possibly using Force Illusion, and Luke killed the Baron before escaping the Valley.