Etc.

The new look in professional sports stadiums: convertibles

Although not every new big-league stadium is built with a retractable dome, clearly that is the trend. Since Toronto introduced the world's first stadium with a fully retractable roof (Skydome, since renamed the Rogers Centre) in 1989, seven more have opened across North America, with another three in the planning or construction phase. Still others are popping up overseas. The advantage, of course, is that games can be played outdoors when conditions are favorable, but under cover when they aren't.

At the Rogers Centre, the roof can be opened or closed in 20 minutes. At Houston's Reliant Stadium, which opened in 2002, it takes only 10 minutes to cover the field, which features real grass. (Artificial turf is still used in Toronto.)

Stadiums with retractable roofs in North America, including several slated to open in the coming years, with the cities where each is located and year it was, or will be, opened: