So in China they have a waterslide 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.
So are you packing bags yet? If you're interested, it's in Lishui, China, which is about 400 miles south of Shanghai.