Cerro de la Bufa (Guanajuato, Mexico)
Scott Gilpin proposes starting / finishing an FKT at the Teatro Juarez in Guanajuato:
Starting from in front of Teatro Juarez, run to the cross at the top of "La Bufa", and return to your starting point. There are many possible variations - the posted GPX is what I found to be most efficient for myself. Others may find better options.