The history of polio (poliomyelitis) infections began during prehistory. Although major polio epidemics were unknown before the 20th century, the disease has caused paralysis and death for much of human history. Over millennia, polio survived quietly as an endemic pathogen until the 1900s when major epidemics began to occur in Europe. Soon after, widespread epidemics appeared in the United States. By 1910, frequent epidemics became regular events throughout the developed world primarily in cities during the summer months. At its peak in the 1940s and 1950s, polio would paralyze or kill over half a million people worldwide every year.The fear and the collective response to these epidemics would give rise to extraordinary public reaction and mobilization spurring the development of new methods to prevent and treat the disease and revolutionizing medical philanthropy. Although the development of two polio vaccines has eliminated wild poliomyelitis in all but two countries (Afghanistan and Pakistan), the legacy of poliomyelitis remains in the development of modern rehabilitation therapy and in the rise of disability rights movements worldwide.