The Flash #125

The Flash Vol. 1 #125 (1961)

• The Major Key: First appearance and origin of the Cosmic Treadmill.
• Key Fact: Features a time-travel team-up between The Flash and Kid Flash.
• Historical Significance: This issue established how speedsters travel through time in the DC Universe. The Cosmic Treadmill became a staple for decades, appearing in major events like Crisis on Infinite Earths and Flashpoint .

Synopsis

• "The Seesaw Mission!": While testing a new invention—the Cosmic Treadmill —Barry Allen and Wally West accidentally trigger a time-travel vibration. They are pulled into the year 2287 A.D., where they find Earth caught in a war between two alien races. The speedsters must use the Treadmill to hop back and forth through time to gather the components needed to save the future planet before returning to their own era.
• "The Mirror Master's Invincible Bodyguards!"(Backup Story): This issue also contains a backup feature where the Flash must contend with more of Mirror Master's trickery involving light-based illusions.