Christmas we will go to Serengeti

I've never heard anyone ever say 'on Christmas'; 'on Christmas day', certainly, but not simply 'on Christmas'.

The speaker is saying a different sentence than the one that is written.

Or "We will go to the Serengeti Christmas." or "Christmas we will go to the Serengeti."

On Christmas (or At Christmas time) we will go to the Serengeti.

true!!!

Maybe Serengeti means nuts? That's what you'll go when doing this course.