Few people are aware of the fierce technological arms race taking place in theme parks around the world. Rides are becoming bigger, faster and more thrilling to go on each year: and the amount of money being used to create rollercoasters is spiralling upwards, as fast as the cars are designed to drop. Our very own Alton Towers opened The Smiler this year, the world’s first 14-loop rollercoaster, at a cost of £18 million (almost $30 million). Next year, the US plans to strike back with a series of taller, longer and faster rides, each designed to push the limits of human endurance: but how far can rollercoasters go before people start to get hurt?