Abstract
The well-known saying of "Seeing is believing" became even more apt in biology when stimulated emission depletion (STED) nanoscopy was introduced in 1994 by the Nobel laureate S. Hell and coworkers. We presently stand at a juncture. Nanoscopy represented a revolution in fluorescence microscopy but now is a mature technique applied to many branches of biology, physics, chemistry, and materials science. We are currently looking ahead to the next generation of optical nanoscopes, to the new key player that will arise in the forthcoming years. This article gives an overview of the various cutting-edge implementations of STED nanoscopy and tries to shine a light into the future: imaging everything faster with unprecedented sensitivity and label-free.