I sawed off the topmost level with a Dremel, for the other levels I used a heat gun to soften the glue and then pried them apart. The "pry point" is the small gap between the sections, just above the animated train "disc". Be careful not to warp the train "disc", use the heat sparingly and gently pry all around (I DID warp the bottom disc, and gently reheating it and pressing down on the warped section helped to straighten it back out so that it worked again). This worked on all the levels and probably would also have worked on the top level (that I sawed off). The only thing I saw that held each level to the next were the 4 "pillars" with the long screws, no need to remove anything else. I disassembled the tree to improve the inner lighting, which does a poor job illuminating (from the inside) some of the buildings around the tree. I hot-glued an LED light string on the interior, and very please with the look. I have pix of the disassembly process if anyone would like to see them, let me know.