Babe Ruth's 60th Home Run
Below is a nice video clip of Babe Ruth's 60th home run of the 1927 season. His 60th homer came on September 30th, 1927 off of Tom Zachary. Ruth's record stood until it was broken by Roger Maris in 1961, then wasn't challenged again until baseball's steroid era in the late 90's.
The home run record was actually first established by Ruth in 1919, when he belted 29 homers for the Boston Red Sox. He broke the record twice more before the 1927 season.
One fun fact about Ruth's incredible 1927 season: he hit 14% of all home runs in the league that year - a feat that hasn't been approached since.