The British Medical Journal is launching a competition to decided the greatest medical breakthrough.
Present-day medical experts are championing discoveries from the last 166 years.
Professor Johan Mackenbach, Erasmus MC, University Medical Center, Rotterdam is supporting sanitation.
The Industrial Revolution, which led to the mass movement of people from rural living to towns, also brought with it the need for sanitation.
The construction of a London sewer in 1859
At first the link between crowded living conditions and illness went unrecognised and infectious diseases exacted a huge toll of illness and death.
Tuberculosis, dysentery, diphtheria, typhoid, measles, smallpox and intestinal diseases were all rife.
But it was the cholera epidemic of the mid 19th century which concentrated minds.
John Snow, involved in the development of anaesthesia, was the one to show that shutting off a particular pump, in London's Broad Street, stopped the spread of cholera in the area.
But it was Edwin Chadwick, a lawyer who had designed the 1834 Poor Act, who came up with the idea of sewers and piped drinking water linked to people's living accommodation to cut the risk of infection from poor urban drainage.
It took decades for his idea to be accepted, either in Britain or in Europe.
But they were, and between 1901 and 1970, deaths from diarrhoea and dysentery fell by around 12% in the Netherlands and England and Wales.
In the 21st century, adequate sanitation is still a major problem in the developing world.
Unsafe water, sanitation and hygiene was estimated to account for around 88% of the 1.8 million deaths from diarrhoeal disease in low and middle-income countries in 2001.