How to break into an encrypted hard drive?

I encrypted my external hard drive with a password a long time ago and now I forget the password, the hard drive has my high school work that I would like to recover. I was able to find a way to completely erase the hard drive but that isn’t what I'm looking for. Is there a way to be able to get into the hard drive? perhaps a program that will attempt every possible combination until it breaks in? since the hard drive does not have a limit to how many attempts I shall attempt. Your suggestions would be very helpful and I'm sure I'm not the only one who have encountered this issue.