Yesterday I was working on

Yesterday I was working on an internet scavenger hunt for the kids (it teaches them how to use search) and I came up with a question along the lines of what day of the week was January 7, 1576? Which isn’t the easiest thing to find on the internet. I stumbled accross more information on the Julian and Gregorian calendars, really just the tip of the iceberg as far as information about the calendar goes. There’s a lot of math and thought put into the various types of calendars out there. I also found a virtual model of stonehenge.