tower of the invention which comprises a cast multi part transition unit a sideview is shown on the right of the line of symmetry while the left portion of fig3 is a vertical section the lattice tower 42 is shown cropped and constitutes the lower tower segment essentially consisting per se of four corner posts 43 and diagonal struts 44 the tubular tower 47 also shown cropped and its walls 48 constitute the upper tower segment one embodiment mode of the transition unit 50 is in the form of a cast concrete shell with a wall 52 and arch shaped clearances 53 in its upper region 60 the transition unit is connected by a flange connector 61 to the tubular tower 47 and in its lower region 70 by four junction plates 71 to the corner posts 43 of the lattice 42 in the upper region 60 of the transition unit 50 the wall 52 smoothly merges into an annular two row screw flange 64 the wall 48 of the tubular tower 47 is welded to a t flange 62 which by means of an inner circle of screws 66 and an outer circle of screws 68 is screwed to the flange 64 of the transition unit 50 the inner set of screws 66 is a conventional steel construction feedthrough system whereas the outer set of screws 68 of this embodiment mode is a blind hole screw system because in this manner the thickness distribution of the wall 52 of the transition unit 50 is especially advantageous for optimal force distribution obviously the wall 52 of the transition unit 50 may be extended slightly further outward whereby the outer.