Why are there flags flying all over the place today?

Why are there flags flying all over the place today?  Because it's Pioneer Day, celebrated every July 24th in Utah.  That's the day in 1847 that Brigham Young and the original Mormon pioneers staggered into the Salt Lake valley to establish the first permanent settlements in what is today Utah. 

I didn't know this myself until just a few minutes ago :)  When we got back from our walk this morning, I noticed that the local Boy Scouts had planted a flag in front of our house.  This is a fund-raising activity they do – for $35 a year, they put up a 3' x 5' flag on a wooden pole, on 12 holidays a year.  Darned near everybody in town does this, so they're raising a few thousand dollars a year this way!  This morning, though, I had no idea why the flag was there.  One Google query and I had it...