Houston Astrodome

The peak of the stadium's dome stands eighteen stories above the playing field and originally consisted of skylights designed to allow natural light through the roof of the dome. As a result, the domed stadium was able to feature a grass playing field. However, the clear roof sometimes focused rays of light in ways that created an extreme glare and made it impossible for outfielders to see a baseball in the afternoon sun. In response, the skylight panels were coated in semi-clear paint. When this caused the grass to suffer from lack of sunlight, the stadium's management designed an artificial turf playing surface. As the stadium had become known as the Astrodome, the artificial surface became known as "Astroturf." 

The Astrodome also served as home to former the Houston Oilers following major renovations in order to accommodate the two different playing fields. In Fall of 1989, capacity for the stadium increased to 54,816 as the grandstands were extended into the outfield. The original scoreboard was replaced by new video boards in the upper deck. The two manual scoreboards were added as part of the outfield walls in both left and right fields. The Oilers later relocated to Tennessee in order to have their own stadium.

The future of the Houston Astrodome is in question, but its credentials as a historic site were confirmed by the stadium's placement on the National Register of Historic Places in 2014. The stadium has been home to national political conventions, championships of multiple sporting events, and a bout between Muhammad Ali and Cleveland Williams for the World Heavyweight Title. It also housed thousands of people who lost their homes during hurricane Katrina in 2005.