London, UK, was once the leading maritime trading hub in Europe. From the Middle Ages, ships carrying goods produced inland would follow the Thames River to the sea, sailing on to Scotland and Ireland. The first major environmental disaster in London after the Industrial Revolution was a cholera outbreak, resulting in significant loss of life. During the 1853~1854 epidemic, over 10,000 people died in London and around 23,000 across Great Britain. This cholera outbreak gave rise to the field of epidemiology, the foundation of modern preventive medicine, and prompted European cities of the time to adopt scientific sanitation measures.