Because there had to be at least one Three Dog Night track on this list. Might as well go with a mostly forgotten, comparatively minor hit about how humanity just keeps destroying the planet, one city, one neighbourhood, one family at a time. Because much as the official hype might tell us that the early 1970s were all about your Led Zeppelins and Elton Johns and David Bowies, the airwaves would have been awfully bare without the hit machine who took their name from a pre-central heating turn of phrase for a very cold night.