On new Super Mario Bros how do you get to the cannon on world1?

Answer 1

If you get a shell and just past halfway in the first castle there is a green pipe that shoots you up. When you fall down go through the door. In the top right corner of the moving blocks you can see a gap. Go through the gap and you will come down through a pipe. You can't do this without a shell. Then run and when you turn into a sliding shell destroy the blocks that block your path and then go through the pipe on the top right and the canon will be unblocked. after that, the cannon will take you all the way to world 5!!!