How Did That Happen?

Since I'm singing this afternoon (with the Oakland Symphony Chorus) at the 75th anniversary celebration for the Golden Gate Bridge, the subject came up yesterday morning in the hot tub at the gym, as we all thawed out after the water aerobics class.  Somebody asked, didn't a lot of people walk on the Bridge at the 50th anniversary celebration? 

And the hot tub group agreed, yes, they did, a ridiculous and uncountable number of people walked on the bridge at the 50th anniversary celebration - so many people that the arch of the bridge visibly flattened, scaring the daylights out of every engineer who could see it.  (The Bridge web site estimates 300,000 people walked on the bridge that day.)  We all agreed, yes, we remembered that; and that's why they are not letting people walk on the bridge this time.

Then someone said, "That was twenty-five years ago??  How did that happen?"

And nobody had an answer.