The Bubonic Plague is the BEST example of spatial diffusion.
Explanation:
Spatial diffusion basically involves all processes which contribute towards the migration within a geographical area and associated with expansion or relocation. Bubonic plague pandemics did not remain localised to just one area but spread to distant places at a very rapid rate, killing thousands of people.
The third and the latest pandemic originated in Eastern Asia but soon spread through and into port cities all across the world. This type of migration of the disease is an excellent example for a spatial diffusion.
