Ancient people figured-out the mechanics of this back in the Stone Age and attached special religious meaning to it, to that mystical moment of the reversal, the beginning of the "days getting longer" (as we say). The ancient Northern Europeans developed this into a major holiday. They held elaborate celebrations, which they called Yule or Yuletide, and their descendants continue to celebrate "the holidays" at the same time.
I wrote about the summer solstice in post-92.
2013's is the first Yuletide during which this weblog has existed, but hopefully not the last!
Thanks for reading.