man skateboarding at skateboard park
skateboarder doing a trick
a man skateboarding on a rail
Man on a skateboard.
The picture was taken at a skate park. 
the man is skateboarding
the man is trying to keep balance
the people are at a skatepark
The skateboarding area is made out of concrete.
a skateboard park 
a young man is riding a skateboard at a skating park while people watch