Medical geography, sometimes called health geography, is an area of medical research that incorporates geographic techniques into the study of health around the world and the spread of diseases. In addition, medical geography studies the impact of climate and location on an individual’s health as well as the distribution of health services. Medical geography is an important field because it aims to provide an understanding of health problems and improve the health of people worldwide based on the various geographic factors influencing them. Medical geography has a long history. Since the time of the Greek doctor, Hippocrates (5th-4th centuries BCE), people have studied the effect of location on one’s health. For example, early medicine studied the differences in diseases experienced by people living at high versus low elevation. It was easily understood that those at living low elevations near waterways would be more prone to malaria than those at higher elevations or in drier, less humid areas. Once people then stopped drinking the water, the number of cholera deaths dramatically decreased. Snow’s use of mapping to find the source of disease is the earliest and most famous example of medical geography. Since he conducted his research, however, geographic techniques have found their place in a number of other medical applications. Another example of geography aiding medicine occurred in the early 20th Century in Colorado. There, dentists noticed that children living in certain areas had fewer cavities. After plotting these locations on a map and comparing them with chemicals found in the groundwater, they concluded that the children with fewer cavities were clustered around areas that had high levels of fluoride. From there, the use of fluoride gained prominence in dentistry. Though the reasons for these variations were not fully understood at the time, the study of this spatial distribution of disease is the beginnings of medical geography. This field of geography did not gain prominence until the mid-1800s though when cholera gripped London. As more and more people became ill, they believed they were becoming infected by vapors escaping the ground. John Snow, a doctor in London, believed that if he could isolate the source of the toxins infecting the population they and cholera could be contained. As part of his study, Snow plotted the distribution of deaths throughout London on a map. After examining these locations, he found a cluster of unusually high deaths near a water pump on Broad Street. He then concluded that the water coming from this pump was the reason people were becoming sick and he had authorities remove the handle to the pump.