Historian Guðjón Friðriksson gives a figurative lecture at Reykjavik Municipal Archives about the history of Reykjavík's sewage system, from primitive open drains to drains, treatment plants and outlets far out to sea. In 2020, Guðjón's book Cloacina was published on this subject. As in other cities in Western countries, the sewerage system is mostly hidden from the eyes of the citizens, and there is a risk that many underestimate its significance or take it for granted in a lack of thought. It is, however, one of the main prerequisites for the well-being and health of city dwellers. The history of sewers is therefore at least less significant than that of other basic elements of the city system, such as the school system, health services or electricity supply.