1578
Sea Level
(imgs.xkcd.com)
Alt text: They're up there with coral islands, lightning, and caterpillars turning into butterflies.
That's just our bias talking. There's certainly many other wonderful events we missed by a couple million years. We just think the moon size is special because of this coincidence.
Like the dinosaurs probably being around while the earth still had rings, right?
I didn't know that fact, but yeah