Firstly, we have to think about what makes a medical advancement the greatest; if it's the bigger number of lives saved, I think the greatest medical advancement is the invention of vaccines and antibiotics, together with the general improvement of sanitation: since their introduction, they have saved hundreds of millions lives all over the world, blocking the spread of deadly diseases and even deleting some of them (like smallpox), whereas a sanitation improvement reduced focuses of infections which caused illnesses, like diarrhea, that were (and in some places on earth still are) one of the main causes of death, especially for children.instead, if we think to a short period of time and we regard to the greatest medical advancement as the most innovative and ,in a way, revolutionary one, probably the most important are medical robotics and biotecnologies, such as mechanical prostheses, for the patient's living conditions improvement, and stem cells studies, for the possible future applications, not counting anticancer research and new generation drugs, which hopefully will lead to a defeat of this terrible and high mortality rate disease, which affects, in its various forms, more and more people every year everywhere.