abstract: The lectures deal with open and solved questions concerning geometric properties such as symmetry or convexity of solutions to variational problems. Methods include but are by no means limited to Steiner symmetrization and maximum principles. Some of the problems covered in the course will be Newton's problem of minimal resistance, the hot spot conjecture, variants of the Faber Krahn inequality, the opaque square, overdetermined boundary value problems and bodies of constant width. The lectures address also the phenomenon of nonsymmetric solutions to symmetric problems.