Since 2008, Soldier Field reportedly has recycled 195 tons of cardboard, 132 tons of plastic and glass and 78 tons of aluminum. Even the sod on the field gets recycled -- 5,588 tons of it so far.
"When we do have the need to re-turf the field, that turf is re-ground and moved to other park district facilities," Luca Serra, Soldier Field, said.
The tunnel the players use to get to their locker room is just one of the areas where more than a thousand lights have been switched to low-wattage energy-saving LEDs.
"They use a lot less electricity, a lot more efficient and actually give off more light," Luca Serra said.
Perhaps one of the stadium's crowning jewels is the accessible park that's actually a green roof.
"Having the grass and the trees, although it looks like a park, that green roof keeps the north garage cool in the summer time and warm in the wintertime," Serra said.
Behind-the-scenes tours at Soldier Field cost $15. Find out how you can go behind the scenes at soldierfield.net