Using Morse theory one can show that a smooth manifold is homotopic to a CW complex.
– SethMar 27 '15 at 15:38
2
Better than that, @Seth, they all actually are CW complexes. (Instead of contracting the handlebody diagram down to the cores, just give the handles a workable CW structure; that or just pick a triangulation.) I think topological manifolds are all homotopy equivalent to CW complexes. If you google this question you should find some MO questions that help.
– Mar 27 '15 at 16:09