The Niels Bohr Institute (NBI) has played a leading role in the development of nuclear spectroscopy at high spin and more particularly the study of rotational motion. Indeed, it laid the theoretical foundation stone and contributed to the birth of the workhorse of the field: the Compton-suppressed Ge array. In this article, we will focus, with special emphasis on the contribution of the NBI, on the properties of rotational motion at high excitation energy and on chaotic phenomena associated with nuclear superdeformation.