The Five Sisters(Man made hills) in Scotland.

The Five Sisters are Bings (Hills) made from a rock called Shale that was mined historically. Through a chemical process oil was extracted from the rock, and the rock then discarded through a conveyor belt system making the Bings. West Lothian in Scotland is the only place in the world that has these Shale Bings i believe. When i was growing up they were pink which is the natural colour. However know they have been taken claimed by nature and are green.