NASA planned 13 manned missions to space, starting with Apollo 8. The first 10 went relatively fine (well, except for Apollo 13). But Apollo 18-20 never got off the ground. Literally. Apollo 20 was canceled first; its rocket was needed for another project. Then a series of congressional budget cuts required NASA to scale back on costs. In September 1970, Apollo 18 and Apollo 19 were scrapped. These days, you can see Apollo 18's Saturn V rocket lying on its side in Houston. It is now essentially a $225 million lawn ornament.