One card in the third round was completely white. It was something around 0 year.
Anyway, that pretty simple, but fun and educational game. Works pretty well.
Author Comments
The follow-up to the similar game about ancient Rome
http://www.newgrounds.com/portal/view/676796
Each card describes a historical event or era, which you should try to date as precisely as possible by clicking on the timeline below it. If you'd like a head start, we have a crash course on the game's own website
http://athleticarcade.com/educational/timeline/firststates/
The game uses localStorage for scores and won't work if your browser is set to block third part cookies/localStorage. Uncheck or make an exception for uploads.ungrounded.net (the domain of Newgrounds iFrame content).
AthleticDesign responds:
Thanks, it is a bug I have encountered before and I actually thought I had finally got rid of it. Not so...
Glad you liked the game - you obviously did very well.