We describe recent results on the construction of rotating black hole solutions in higher dimensions, and some of their applications in string and M-theory. Problems associated with the proper definition of mass in background spacetimes that approach anti-de Sitter space at large distance are discussed, and the relation to black-hole thermodynamics is described. The relation between bulk and boundary quantities in the AdS/CFT correspondence is discussed, including the contribution from the Casimir energy. Finally, we discuss NUT type generalistions of the higher-dimensional black holes, and a remarkable inversion symmetry of the five-dimensional Kerr-AdS metric.