Where's Grandma?

Emmy:  Mommy, where's grandma Debbie?
Me:  She's on vacation.
Emmy:  Oh.  She's on vacation in Canada?
Me:  (puzzled as both Brad and I turned to look at each other).  No honey, she's in Arizona.  But, where did you learn about Canada?

Neither of us have talked about Canada that I can recall.  She must have learned it from her class at daycare.  I just don't know how she even knows what/where Canada is?