Yes, walking is an Olympic sport. In the early Olympics they had walking events as short as 1,500 m, but quickly people realized that walking short distances was not quite that exciting and eventually running was invented. Currently they still race the 20 and 50km for men and the 20km for women. Since you were wondering, what separates it from running is that one foot has to be in contact with the ground at all times and the leg must be straight until the racer’s body crosses over it. I’m sure this is very hard, but it looks kind of ridiculous.