Most everybody probably had trouble staying awake in history class, but this won't take too long. City Stadium was the original name of Lambeau Field, but Old City Stadium still exists, it was the site of the Packers games from 1926-1956, and is still used by Green Bay East High School.
The Packers announced that they will hold a charity fundraiser and practice at Old City Stadium on July 31. Currently the stadium only has a 2,300 seat capacity, but stadium had seating for 25,000 back in 1956. Here is a sweet old picture before an NFL championship game.
My favorite factoid about Old City Stadium was that the teams used the locker rooms at East High School so visiting teams often dressed at the hotel instead.