I lived in Hawaii for 5 years in my early 20's and I used to see a huge painting on the side of a building with a life sized humpback while breaching out of the water. The painting was later covered up when they built a parking garage over it.
Last I heard there are 86 Whaling Walls around the world. His goal is to paint 100 walls. You need to find one and do the gps thing.
To get credit for the cache you need to:
Find a Whaling Wall painted by Wyland
Take a photo of the FULL wall
Take a second photo with you and the gps
Post the coordinates
Normal locationless rules apply.
If, by reading the logs you find a wall near you, and you decide to visit, please post a NOTE with a photo of you at the wall.
Some useful links:
http://www.pitt.edu/~bdobler/discovery/wyland.html
http://www.beachcalifornia.com/lbwyland.html
http://www.kidzwerld.com/site/p2021.htm
http://www.wyland.com
george