Both the Olympics and the World Cup are two huge sporting events that draw much attention from the public. If you want to know which event or set of events is bigger, that would depend on a few things. First, the Olympics cover many sports including boxing, swimming, basketball and many other sports. So, it is a big event for each individual sport. Many people live their lives to compete at the Olympic level because there are only a few other championship tournaments to compete in.
However, to them, the Olympics is the biggest event. When analyzing just soccer since this sport is in both events, it would also depend on the country. Many Americans in the United States believe the Olympics is the bigger event whereas Europeans believe the World Cup is the bigger event.