When cities transform into a colorful world of lights as darkness falls, it's often only possible to estimate their contours, which depending on the perspective can draw the attention to key details or trivia. In fluorescence microscopy, biological cells are marked with fluorescent dyes and excited to luminesce in specific areas by optical switches– like a city at night. However, this light is usually too faint for small, rapid objects, or even goes out after a while. This is known as " fluorescence bleaching".