In the talk I will give an introduction to hyperkahler manifolds. These are Ricci flat Riemannian manifolds with holonomy contained in Sp(n). Alongside the study of Calabi-Yau, G2-, and Spin(7)-manifolds they form the subject of special/exceptional holonomy. In dimension 4 the notions of hyperkahler- and Calabi-Yau manifolds coincide. In my talk I will in particular describe the construction of rotationally symmetric examples.
