Major League Baseball sets a single-day attendance record as 717,478 fans show up for 17 games. It easily breaks the 640,412 record set on July 3, 1999.

This Day In Baseball

On July 29, 2007 — Major League Baseball sets a single-day attendance record as 717,478 fans show up for 17 games. It easily breaks the 640,412 record set on July 3, 1999.

Source:
Baseball Reference July 29
National Pastime
Retro Sheet
Hall of Fame
SABR Games Project
Replay The Game