1918 RFC (Royal Flying Corp) becomes RAF (Royal Air Force)
2008 Excavation to determine true age begins at Stonehenge
(I know this is a bit of a cheat for an "on this day", but it's just an excuse to link this little Flash movie animation of the birth, growth and decay of the world heritage monument for anyone with 79 seconds to spare. Quite amazing how big it once was.)
It accurately marks the position of sunset at the winter solstace, which told people then that winter had reached its peak and spring was on the way, so it could be agricultural or religious (if they made any distinction then). Strangely, modern day pagans, calling themselved Druids, after a sect around a couple of millenia ago, dance silly dances and sing silly songs at sunrise on the summer solstace (completely in the opposite direction), which can have had very little reason for celebration (It's all downhill from now on - bummer !), but is obviously a much nicer time of year to be out and about in flimsy clothing.
Solstace (static sun), rather than equinox (equal night), so actually when the night and day are most unequal. The shortest and longest days of the year.