Sewage contains the waste of a city and its inhabitants. It is possible to find almost any microorganism in sewage. In fact, in the sewer system can be found quite unexpected creatures. About 1960, sewer workers in New York City found a number of live and exceeding unfriendly alligators in that city's sewers. These animals, gifts to city residents, had been disposed of through household toilets. The warm, wet environment of the sewers, rich in food, was excellent for rapid growth.