While living in Milan, Leonardo da Vinci recorded massive plague outbreaks in major European cities. The master tried to understand what made them so vulnerable to dangerous epidemics. This led to the idea of designing and building a special 'clean' city from scratch, where people could live in sanitary conditions without risk to their health and lives.
According to the scientist, the area was to be divided into several levels. These, in turn, were to be provided with minimum sanitary standards, and conduits were to be provided for the timely disposal of waste water. Water was to be supplied to each structure by means of a hydraulic device. Unfortunately, no public funds were allocated for the construction of the Miracle City.