How to be not afraid of heights?

I am REALLY afraid of heights. Whenever I saw a roller coaster or even just looking out of my window, I am thinking about how it would feel like falling down. At a primary 5 camp, I cried but nobody knew. I just really afraid of falling or even just be at a high place. But when the camp was over, I recapped everything that happened. I told myself that it was fun. Again, I would be scared when I see it. What can I do to really cure myself from this haunting fear?