My wife and I, along with my brother, my sister-in-law, and my niece started the day by visiting Waimea Canyon. Located on the west side of the island, it has been described as the Grand Canyon of the Pacific. Unfortunately, I've never been to the Grand Canyon but even so I can say that this description is probably accurate. The canyon is over 4000 feet deep at its deepest point despite the fact that it is only a few miles long.
My brother took his family to Barking Sands beach while my wife and I carried on the trail to catch a view of the cliffs of the Nepali coast from the top. (Nepali simply means "the cliffs" so in a way that statement is somewhat redundant).
Day three was also the day I first tried snorkeling. My wife thought that I should at least try swimming in the ocean before I tried scuba diving. The experience was remarkable. Unfortunately, I had problems with my snorkel so I swam without it and just used my fins and mask. Nevertheless, my first view below the waves will remain in memory forever. There were dozens of different types of fish and many were very colorful. It was almost like swimming in an aquarium. Sadly, my first shots didn't turn out that great as I wasn't used to framing a shot while being moved along up and down and side to side by the waves.
The Flickr set can be found here