There are currently more than 750 such areas in the National Wilderness Preservation System comprising over 109 million acres -- roughly 5% of the United States by area. Need a refresher from the other 95%? The Active Times picked 10 wild places in the lower 48 states that are truly wild.
Polio, which struck children disproportionately, could attack the central nervous system and cause muscle deterioration, paralysis and even death. American virologist Jonas Salk, who was born 100 years today on October 28, 1914, developed the worldâs first safe and effective polio vaccine.
Well like many medical breakthroughs, there were a succession of findings by many scientists which led to an ultimate polio vaccine. But it was a scientist by the name of Dr Jonas Salk who, with the help of his colleagues at University of Pittsburgh Medical School, discovered the polio vaccine itself. Dr Jonas Salk was the son of Orthodox Polish-Jewish immigrants and was born in New York in 1914.