The Kansas City Royals Jumbotron is currently the largest in professional sports at 84 feet wide and 105 feet tall, The Arizona Diamondbacks Jumbotron is the second largest. It is 144 feet wide and 55 feet tall. Both of these will soon take a back seat to the jumbotron at Cowboys Stadium when it opens in 2009, it will be 160 feet wide and 72 feet tall.
Giants stadium has the second most seating capacity
colts
ANZ stadium in Sydney (Formely known as Telstra Stadium or Stadium Australia) has a capacity of 82000.
Yankee Stadium
Spartan Stadium has a seating capacity of 75,005 people.
Sun Devil Stadium has a seating capacity of 56,232 people.
Atlanta-Fulton County Stadium's seating capacity for baseball was 52,007 and for football was 60,606. The stadium was imploded on August 2, 1997.
150,000. The Rungrado May Day Stadium in Pyongyang, North Korea.
Dodger Stadium in Los Angeles, California is the largest ballpark in the United States by seating capacity, with a capacity of around 56,000 seats. It is also the third-oldest ballpark in Major League Baseball.
The Pennsylvania State University's Beaver Stadium. 110,000
Kinnick Stadium has a seating capacity of 70,585 people.
If you mean by stadium, an amphitheater, Rome's largest was the Colosseum, having a seating capacity of 50,000. Now here's the tricky part, "stadium" in Latin could refer to a race course. If that's what you mean by the word stadium, it was the Circus Maximus which had a seating capacity of 150,000.