tony hawk is the most famous skateboarder in the world. he has won more skateboarding competitions than anybody else. he has also invented more than eighty skateboarding tricks and was the first person to do one famous trick called the '900'. the 900 is a 360 degree somersault done two and a half time in the air! it took him six years to learn the 900. he finally did it in 1999. since than only four other people have been able to do it.