@valleyforge there are four types of construction cranes
https://en.m.wikipedia.org/wiki/Crane_(machine)
@valleyforge sightlines? Cranes support the load from above, so you can pretty safely assume there's no obstruction over the working end of the machine. But if you're lifting a load onto a high horizontal surface, or even holding in place a load above a horizontal surface, you'd see only its underside from below.
@lucifargundam I mean a tower crane. Why have someone climb up there instead of control it from the ground?