Unstable objects are good candidates to trigger new phenomena, but bad targets for every mean of observations. A question regarding observation arises: Can we stabilize unstable objects in a noninvasive way? In 1992 Pyragus gave an affirmative answer for ODEs, by introducing suitable time delays. It was until 2017 that Schneider generalized such ideas to PDEs, with spatio-temporal delays, and established the control triple method. I will explain this method, and her pioneering result that stabilizes unstable rotating waves on the unit circle.