I think it should be outdoors. With an indoor stadium, it takes away the advantage of the cold weather in Minnesota, and they add about $150,000,000 to the price of the stadium. With a retractable roof, it would be shut during winter or when it is raining and only be open for the first month of the season, and they also add about $150,000,000 to the price of a stadium. With an outdoor stadium, there is the advantage of cold weather, and it is fun to watch a football game when it is raining or snowing.