What is an excellent topic to base my Biology poster on?

Question

What is an excellent topic to base my Biology poster on?
It's suppose to be on poster board, and based on one major research discovery in the past century that relates to the course.
The poster presentation needs to describe the discovery, its impact on human society, the person (s) involved, when and where it occurred and any other pertinent information.


Thank You for your help should you decide to accept this mission. :)

Answer 1

The discovery of DNA, the double helix (don't forget a woman
did the initial discovery, but men got the Nobel Prize
The invention of the electron microscope (this is really
interesting and would be my choice--allowed researchers
to finally "discover" viruses)

Answer 2

The human genome project would be good. It was completed in 2003 and identified all of the genes of the human genome. Your poster could be a big double helix. What level of education are you currently at?