This issue celebrates a double anniversary for the neuroscience of consciousness and one of its most central notions, the neural correlates of consciousness (NCC). In 1990, Francis Crick & Christof Koch published "Towards a neurobiological theory of consciousness" in which they put a research programme on the scientific agenda: The search for NCCs. In 2000, in the seminal anthology "The neural correlates of consciousness: Empirical and conceptual questions" edited by Thomas Metzinger, David Chalmers answered the question "What is a neural correlate of consciousness?". This special issue, edited by Sascha Benjamin Fink, celebrates this double anniversary with seven original articles and will be extended by a second issue in early 2021.