The world's largest - legal - base jump takes place in West Virginia

Many of you will likely have heard of base-jumping. That's where someone leaps off a tall fixed structure - like a cliff or a skyscraper - and parachutes back to earth. It's increasingly popular - but not always legal. However - in the US state of West Virginia - once a year - they let hundreds of people base jump off one of the highest road bridges in north America. The BBC's Tim Allman has more.