George and Amal Clooney: ~ $20 million, London
George and Amal Clooney are the epitome of a Hollywood power couple. With a growing family, they had moved into a mansion in Berkshire in 2014 which has a 60-foot pool, cinema, and tennis court, to name just a few features. Best of all, it comes with a modern irrigation system which gives the whole estate an environmentally positive treatment.