Rock Climbing is a very dangerous sport because the climbers could hurt themselves by falling from a high distance. If they fall and do not have a harness on them they might hurt themselves and maybe kill themselves. If they only hurt themselves then they might severely hurt themselves. If you go to the gym then they usually have a soft mat so that if you fall then you wont be badly hurt. Usually you would have some one to hold you up.

Before you climb you should use these calls:

#1. You should say "On belay."

#2. Then they should say "Belay on."

#3. Next you should say "Climbing"

#4. Then you should here the response "Climb on."

Then you can start climbing.