NOAA Beaufort Sea State ImagesThere was a poster with these images at the Seattle Boat Show. I had seen them once before but it was a long time ago and I enjoyed trying to match what I had experienced with the numbers.
Note the descriptions underneath each photo. There is a full description on wiki if you want more information but it is fun just to scroll through these all at once and watch the progression.
All photos are public domain, copyrighted by NOAA.