Like most international events of sport, the idea of brotherhood through competition helped to initiate the Pan American games. Its history, as already noted, emerges during World War II. The idea was to promote a collectivity between the nations in North and South America. Given the height of the war, the games were not actually first played until 1951. The idea of holding a multi sport event every four years was meant to bring a great deal of publicity to the two continents. The games hold meaning, but have been overshadowed by the Olympics and professional competition on the part of the athletes. For example, athletes who are making millions of dollars playing for their professional clubs and organizations are not as willing to risk injury and/ or participate in the Pan Am games. Despite this, the playing for national identity in sports such as soccer still entrances much of the attention in the Pan American nations.
The Pan American Games were to be first hosted in 1942, but World War II pushed the date of the first games back to 1951. The original idea behind them was to promote unity between the various countries of North and South America. Think of it like a regional version of the Olympic games, designed not necessarily to keep other nations in the world out as to allow nations in the Americas to promote their athletes.
The Pan American games are held every four years, like the Olympics, but a year earlier. There has been talk now and again about starting a Pan American Winter Games, but it never really goes anywhere (perhaps because so few countries involved actually experience snow.)
On a more basic level, the point of the games (as in all sporting competitions) is to win and boost national pride. The games bring together people from many nations in a spirit of cooperation and brotherhood.