The Long Arm of The Derrick

Here is a derrick with a very very long arm.The arm is even higher than the buildings surround.There are also some other special vehicles have long arms such as fire engine.Fire engine can rise the scaling ladder to save the people who is trapped by the fire in the high level.I think since the scaling labber can let people stand on,it can be used for tourists to give them a higher view of the city .More than that,I wonder if we can bring bungee jumping on the scaling labbers,it will be very great.People can choose the place for bungee jumping.And then what they need to do is just letting this kind of car comes.