Ride down takes about an hour...
Is it possible there's a better tourist destination in China than the Great Wall? If you're a huge waterslide fan, then yes.
They have one that's about a mile-and-a-half long, and was certified by Guinness as the world's longest mountain/hillside waterslide.
It's a combination waterslide AND rafting adventure. It gets up to speeds of almost 20 miles an hour and lasts for about an hour. If you're interested, it's in Lishui, China, which is about 400 miles south of Shanghai.