Presumably it's pleasant the rest of the time, or near a suitable travel route or natural resources, and because it's easier to build there than higher up the m

Presumably it's pleasant the rest of the time, or near a suitable travel route or natural resources, and because it's easier to build there than higher up the mountain side. E.g. while much newer, the town of Rjukan in Norway which also has a small heliostat, was built specifically due to the nearby waterfalls that provided easy access to power for industrial use, and the valley floor was where most of the town was constructed because that's were the easily accessible terrain was.