Red Moon

One of the lines for "When the Saints Go Marchin' In" I picked up somewhere along the line over the years is, "Oh, when the moon shines red with blood". I didn't really know what it meant until I saw the phenomenon some years back during a lunar eclipse, when the moon took on a reddish hue. 

There's a lunar eclipse tonight, so depending on conditions this may be one of those times the "moon shines red with blood".