(*Adapted by Rafael Luís: rafaelluis@netmadeira.com
updated to Mathematica v.10 by Ross Moore *)

Mandel[x_,y_] := Length[FixedPointList[ (#^2 + x + y*I) &, 0, 70, SameTest->(Abs[#]>2&)]];

DensityPlot[
  Mandel[x,y], {x,-.65,-.4}, {y,.5,.75},
     PlotPoints -> 400, Mesh -> False, Frame -> False
,ColorFunction->(If[#==1, Black, Hue[.9#]]&),
   AspectRatio -> Automatic ]