theFOG got it...It's a long exposure of a waterfall with changing coloured lights behind it. Every time the colours changed, we moved the camera. Hence the title 'Colourfall'. The light streaks are from people walking past holding candles...The whole thing was my boyfriend's idea. He'd tried without any good results and thought he'd let me have a go... well I had to crop down the pic a little bit as there was a huge gap between the last two waterfalls..but I'm pretty happy with the result.