In extreme environments such as ultra-strong magnetic fields and ultrahigh pressure, matter is squeezed and behaves differently, in a manner that cannot easily be understood by our chemical intuition. In strong magnetic fields, for example, a new bonding mechanism has been shown to exist, triggering new experimental activities. In the project 'Molecules in Extreme Environments', the mostly unknown chemistry of extreme environments was studied theoretically and computationally, by means of quantum-mechanical simulations, to help discover and understand new phenomena and to guide experimental work towards their detection.