June 2, 1925. The conversation between manager Miller Huggins and Lou Gehrig in the clubhouse before the game:
Hug: Tired?
G: No.
Hug: Good. You're playing first base today.

Normally Wally Pipp would have played first base, but he sat out that day. Not everyone agrees on the reason why. Frank Graham, reporter for the Yankees and Gehrig biographer, said that Pipp told Gehrig that an old injury around his right eye had flared up. Pipp told Hug that the eye injury was giving him a headache. In response, Hug told him to take an aspirin and a rest, which Pipp did. But, Graham said, the official reason for Pipp's exit was because he hadn't been performing well, and Hug thought a day's rest would rejuvenate the Yankee veteran.

Eleanor Gehrig, who didn't meet Gehrig (and then marry him) until the early 1930s, wrote in her autobiography that the story released to the press was indeed that Pipp had a headache, but instead of resting he took the day off to recreate at the race track.

Another version, this one written by Gehrig biographer Richard Bak, says that during batting practice on June 2, Charlie Caldwell, Jr. accidentally hit Pipp on the temple with a pitch. In which case, a headache would certainly be a legit excuse to skip out on the game. Bak's version says Pipp spent the next two weeks in the hospital with a concussion.

Whatever happened, one fact prevails in every account of that day - Gehrig played his first full game*. He would continue playing first base until he retired in 1939. During all the years in between, he played every game, even games that didn't count towards continuing the streak, such as exhibition and World Series games. Even the All-Star games (started in 1933 by Arch Ward as part of Chicago's World Fair) had Gehrig on the rosters. 

Because Pipp never regained his position at first base, "Wally Pipp" became a threatening phrase to slackers, warning them that if they slack just one time, they could regret it for the rest of their lives. Not that Pipp was sore about being replaced by a rookie.  In fact, Pipp worked with Gehrig to improve the rookie's first-sacker skills. 

That first full game on June 2, Gehrig faired well. On the defense he accomplished 8 put-outs and 1 assist. Offensively he went to the plate 6 times, got 3 hits and 1 run. He would well surpass this first performance in a matter of a few seasons.

"After Gehrig became a regular, he was happier than he ever had been before. He was a Yankee now in all truth. Out there at first base every day, playing in every game," Graham wrote. And no one noticed Gehrig's endurance (not even Gehrig) until 1933. On July 4 of that year, Dan Daniel of World-Telegram pointed out to Lou that he had been playing nonstop since 1925, some 1,200 games. Daniel was not sure of the streak's start date, though; he had to check with his office's records to see if the streak began on June 1 or June 2 of 1925. June 1 Gehrig was the pinch hit for Pee Wee Wanniger. Although he did not produce a hit, the office confirmed that it counted as a played game, thus beginning the consecutive games streak. Daniel did the math and figured out that if Gehrig continued to play in every game, by the end of the '33 season Gehrig would break Everett Scott's record for consecutive games played. Everett Scott, a Yankee who ended his streak the same year Gehrig joined the team, had set the record at 1,307. He was known as the Iron Horse of Baseball.

Gehrig broke Scott's record on August 17, 1933, at Sportsman's Park in St. Louis, MO, becoming the new and more famous Iron Horse of Baseball. There was a bit of hoopla, but nothing like what Gehrig would see when he retired.

Why did Gehrig insist on playing every game? The answer is, "That's Gehrig." That's the way he was raised. He didn't do it to gain attention; he did it because he had spent his life working every day to try to get ahead. Growing up, he had no choice but to help his mother work a variety of jobs every day to earn enough money to scrap by. When a boy grows up in a such an environment, with such a work ethic forced upon him, it's only natural he would become a man who never loses that mindset. "It was strange, his wife, Eleanor, wrote, because there was no particular reason to keep playing without a break, no particular compulsion-- except the fascination to add one more day, one more week, whatever you lost." She called the streak "the tyrant in our life."

Tyrant. Work ethic. No matter what it's called, it was a record that stood for over half a century. Accomplishing such a feat is no easy task, even for a nose-to-the-grind-stone man like Gehrig. He had to play through sickness and pain. During his later years, doctors took x-rays of his hands. He had 17 healed fractures. There were times when the streak could have ended early. Once, during a game in Norfolk, VA, Gehrig was hit on the head with a pitch and knocked unconscious. (Incidentally, players did not wear helmets during Gehrig's career).

The most drastic threat to the streak occurred in 1934, during a game with Detroit. Gehrig suddenly doubled over while he was trying to leg out a single. The first base coach immediately attended him; Gehrig could not straighten his back. Despite worsening pain, Gehrig played the rest of the half inning, then went into the clubhouse to seek treatment from the trainers. Trainers tried massage and heat, but nothing relieved the pain. The rest of the day, it was a constant in his back. He lost a night's sleep because he could not get comfortable. The next day, Gehrig insisted on going to the ball park. But, he came up with a clever and perfectly legal way to get rest while continuing his streak.

When his streak began, all he had to do was take one turn at bat then sit out. So Gehrig easily convinced Yankee manager Joe McCarthy to allow him to do the same again. Gehrig batted lead-off in the first inning, hit a single, was given a replacement player, then he returned to the trainer's table.

James Kahn of the New York Post heard of the incident. He would write later, "This was Gehrig's closest escape from having his endurance mark broken, and it is given in detail because it may hold an additional interest for medical men. These attacks occurred occasionally and escaped accurate diagnosis, invariably doubling him over and making it painful for him to breathe until they wore off in a couple of days. For convenience in reporting them and because of the absence of anything more definite, the sportswriters referred to the attacks as lumbago. Gehrig became quite sensitive to the curiosity of the reporters after a while when these attacks hit him, which they did three or four times over a period of four or five years."

No one knew what caused the attacks, and certainly no one could have guessed that Gehrig would soon fall victim to the horrible disease ALS, a rare and lethal form of sclerosis that deteriorates muscle function.

Guessing, though, was the only thing anyone could do. Teammate Babe Ruth said that Gehrig should take a break from baseball and go fishing (another of Gehrig's passions). Gehrig only laughed at such a suggestion. "Can you imagine me fishing when the Yankees are playing ball?" he rhetorically asked reporters after telling them what Ruth said.

By 1938, the strange depletion in Gehrig's go was noticeable. In 1939, it was obvious. Normally an aggressive base runner, Gehrig was limping in the base paths. His bat's sweet spot was ineffective. Gehrig persisted, working out after practice, trying to strengthen his muscles. But his condition continued on a downward spiral.  Finally it came to the point where Gehrig had to struggle to make a routine put-out at first base. His teammate Johnny Murphy, who had to wait for Gehrig to drag himself to the bag in order to receive his throw, said, "Nice play, Lou." That was the cue he had dreaded. His teammates felt the need to congratulate him on the simplest of chores, like older siblings encouraging their little brother.

May 2, 1939, Gehrig approached McCarthy before the game:
G: I'm benching myself, Joe.
McC: Why?
G: For the good of the team. I can't tell you how grateful I am for the kindness you've shown me and for your patience. I've tried hard, and you know that. But I just can't seem to get going, and nobody has to tell me how bad I've been. I've been thinking, ever since the season opened - when I saw that I couldn't start as I'd hoped - that the time had come for me to quit.
McC: All right, Lou. Take a rest. I'll put Babe Dahlgreen on first base. But I want you to know that thats your position - and whenever you want it back, all you have to do is walk out there and take it. (E. Gehrig, My Luke and I).

Lefty Gomez tried to cheer him up that day, telling him, "It took them 15 years to get you out of the game. Sometimes I'm out of there in 15 minutes."

Gehrig's record stopped at 2,130 consecutive games played. He had surpassed Scott's record by 823 games - approximately 6 years worth of playtime. The record would stand for 56 years; Baltimore's Cal Ripken, Jr. broke it in 1995. No one else has come close.

*Gehrig's professional debut was June 16, 1923, when he replaced Pipp at first in the 9th against St. Louis. June 2, 1925, was the first full game he played.