FANCY a gentle paddle down the Thames? Or a splash about in the Norfolk Broads? Or maybe something a bit more bracing? Like a 120ft vertical drop, straight down the front of a churning, thundering, pounding waterfall into a jagged mess of rocks, froth and vegetation, with just a fibreglass kayak and a jaunty coloured helmet for protection? Perhaps not. Extreme kayaking may not be everyone's cup of tea but, extraordinarily, it is becoming more and more popular as adrenalin junkies further their quest for a high-octane thrill. And as these amazing photographs - taken by professional photographer Lucas Gilman - show, there's now a whole extreme kayaking world out there. In one photo, professional kayaker Pat Keller is a tiny green dot on the La Paz Waterfall in Costa Rica as he plunges 120ft straight down the cliff face at a speed of 300ft per minute. Fellow thrill-seeker Ben Stookesberry launches his bright orange kayak into the thundering waters of the 70ft Lower Mesa Falls, Idaho, in the U.S. In another, fearless Jesse Coombs battles the same waterfalls - man pitted against the almighty force of nature. 'Every time a kayaker goes over a waterfall of more than 40ft, there is a good chance of injury and even death,' says Gilman, who has snapped kayakers in remote spots from Brazil to India. Just taking the photos can be risky - more often than not, the perfect spots for taking pictures are damp, dangerous and alive with snakes, leeches, insects and, occasionally, bandits. 'It's not a pleasure cruise,' he says. 'It's hot, humid and usually in a country that doesn't have hospitals readily available. 'To get the best shot, you have to get to the best location to shoot, which my be in the base of a gorge. 'You have to rappel in [abseil] and battle slick rocks, snakes, bugs - these are places people don't usually want to go. 'I have been known to rappel 100ft into an unknown gorge to get a decent view and I have also been held up in Chiapas Mexico by knifepoint while trying to trek out of the jungle and find a road. They robbed us and let us go.' Every shot he takes involved meticulous planning because the window of opportunity allows no room for failure. 'I try to pre-visualise the shot and usually shoot with two cameras - one acting as a remote - so I have a horizontal and vertical view of almost every situation,' he says. 'There's no second chance with these - you can't ask a guy to go run that 100 footer again.' And just in case you're still tempted to try extreme kayaking, spare a thought for the fearless Keller who swooped down the La Paz Waterfall in his lime-green kayak. He was delighted to escape with only a broken hand - which snapped on impact after his amazing dive.                      - DM