Here's a quick explanation of what BC and AD mean. I also take a peek into the origins of these terms and what is an acceptable labeling system today.

Here's some sources:

https://en.wikipedia.org/wiki/Anno_Do...
http://www.encyclopedia.com/people/hi...
https://en.wikipedia.org/wiki/List_of...
https://en.wikipedia.org/wiki/Common_Era
http://www.livescience.com/45510-anno...

Here's some photo credits:
(in order of appearance)

http://2.bp.blogspot.com/-ECIZD2N2vfI...
http://cdn-3.mrdowling.com/images/603...
https://ih0.redbubble.net/image.10229...
http://www.clipartkid.com/images/618/...
http://www.pngall.com/wp-content/uplo...
http://cdn-1.mrdowling.com/images/703...
http://localexpertinterview.tv/wp-con...
https://www.cavendishschool.com/wp-co...