Chicago's Soldier Field, the oldest stadium in the NFL, is the first NFL stadium to be certified as green. NFL Commissioner Roger Goodell, Chicago Mayor Rahm Emanuel and Chicago Bears President and CEO Ted Phillips were on hand Thursday to announce that the stadium received the USGBCs LEED:EBOM.

Soldier Field, built in 1924 and rebuilt from the inside in 2003, became the home of the Bears in 1971. The stadium's 2003 renovation was followed by a number of environmentally friendly initiatives, which included the use of green cleaning products, electric vehicle charging stations and energy-efficient lighting. And although the Bears have criticized Soldier Field for its terrible sod in the past, it is sustainable sod, say officials.

According to the USGBC, the LEED certification will provide independent, third-party verification that the structure uses strategies aimed at achieving high performance in key areas of human and environmental health: sustainable site development, water savings, energy efficiency, materials selection and indoor environmental quality.

There are more than 200 events held at Soldier Field every year. It is owned by the Chicago Park District.