Which is the largest American Football stadium

Context: NRG Stadium, formerly Reliant Stadium, is a multi-purpose stadium in Houston, Texas, United States. Construction was completed in 2002, at a cost of $352 million and has a seating capacity of 72,220. It was the first NFL facility to have a retractable roof.

The stadium is the home of the National Football League's Houston Texans, the Houston Livestock Show and Rodeo, the Texas Bowl, many of the United States men's national soccer team's matches, Mexico national football team friendlies where El Tri serves as the host, and other events. The stadium served as the host facility for Super Bowls XXXVIII and LI, and WrestleMania 25. The stadium will host multiple matches during the 2026 FIFA World Cup.

NRG Stadium is part of a collection of venues, which are collectively called NRG Park. The entire complex is named for NRG Energy under a 32-year, $300 million naming rights deal in 2000.

Answer: Given the provided text, it's not possible to answer the question about what's the largest American Football stadium. The text only mentions that the NRG Stadium has a seating capacity of 72,220.