The Lagrange Institute (Institut Lagrange de Paris, ILP), established in 2011, unites research groups from the Université Pierre et Marie Curie (UPMC) and CNRS, mainly from the Institut d'Astrophysique de Paris, the Laboratoire de Physique Nucléaire et Hautes Energies, and the Laboratoire de Physique théorique et Hautes Energies with internationally recognized research programs in theoretical and observational cosmology, (astro-)particle physics, and theoretical and experimental high energy physics. The Institute's mission is to advance foundational questions on the origin, constituents, dynamics, and fate of the Universe. The research at the Lagrange Institute can be summarized in 3 central questions: