I presented the BC/AD timeline to the boys earlier this week. You can read about the BC/AD timeline I made here. I chose the style of my timeline from the Keys of the Universe History Album and followed the presentation there as well.
Note: The zero on this timeline does not represent a year. Here is a portion of the script for this timeline from the KotU album:
“Look at our red zero on this time line. This indicates the central point.”
“Now notice all the time before that event. Those years are followed by the letters B.C.
These letters stand for the words ‘before Christ’. There were thousands of years (we don’t
know how many!) before that event happened, but on our timeline here we are just listing two thousand of them.”