A non-solvable Galois extension of $\Q$ ramified at 2 only
  In this paper, we show the existence of a non-solvable Galois extension of $\Q$ which is unramified outside 2. The extension $K$ we construct has degree $2251731094732800=2^{19}(3\cdot 5\cdot 17\cdot 257)^2$ and has root discriminant $\delta_K <2^{{47/8}}=58.68...$, and is totally complex. 
Lassina Dembele, with a supplement by Jean-Pierre Serre