Base jumping is banned in US national parks, but in Switzerland, it’s a growing sport despite the risks. So what is it and why do people do it?

It’s one of the most beautiful spots in the Alps, sheer walls of rock, ice on either side. Snow covered mountains sore into a deep blue sky. It’s a favourite spot for hikers and climbers.

I’m about to go for a base jump.

Base stands for the things you jump from. There is no law against it, although Ellen does admit, it’s not for everyone.

To be able to jump off of a cliff in some of the most beautiful places in the world is probably not something that most people think about doing. It’s not normal.

They made their way out to what’s a bit like a little diving board. And I’m staying firmly on the path. And they are about to jump off. See you later. Good luck. And they are gone, free falling down.

It’s a great feeling of freedom. I love it. I just love the feeling of the air and flying. It’s more flying and falling. Even though you can see the ground coming, the ground rush, it’s just a great feeling of happiness.

I feel so good to have a feeling of just like pure release of happiness and all the, everything good in life is like during that moment.

Down in the valley though, some local farmers are less than happy. He has personally witnessed deaths.

I heard a bang. A base jumper has crashed onto the rock face several times, fell to the bottom of the cliff and died there. I felt sort of angry that someone could put there life on the line like that for just a few seconds of thrills.

In America’s national parks, base jumping is banned. In the Swiss Alps, it’s largely unregulated. And there are accidents. Last summer, Mark Sutton, the man famous for parachuting into the London 2012 Olympics as James Bond died in Switzerland after crashing into the cliff. This April, there were four deaths in a single week. Base jumping is just one of many risky mountain sports. If you are not thinking about the risk every time you jump, you shouldn't be at jumping.

The first thing I do is look back at the cliff and think that I’m gonna go back again.