Covered with 10,000 lights, the Banpo Bridge Rainbow Fountain's coloured water rains down spectacularly in graceful arcs from the double-decker Banpo Bridge. Spanning 1140m, it's the world’s longest fountain, and is best viewed from the island's observation deck or Banpo Hangang Park . The 20-minute show usually happens between late April and the end of August at noon, 8pm and 9pm Monday to Friday and noon, 6pm, 8pm, 8.30pm and 9pm on Saturday and Sunday. Shows are cancelled if it’s raining.