  We prove that the moduli space A_{11}^{lev} of (1,11) polarized abelian
surfaces with level structure of canonical type is birational to Klein's cubic
hypersurface:
  a^2b+b^2c+c^2d+d^2e+e^2a=0 in P^4.
  Therefore, A_{11}^{lev} is unirational but not rational, and there are no
Gamma_{11}-cusp forms of weight 3. The same methods also provide an easy proof
of the rationality of A_{9}^{lev}.
