The crystal-clear waters of Flathead Lake, Montana • photo: via FrigateRN on Flickr
Menorca Island, Spain
Hidden beach on Marieta Islands, off the coast of Puerto Vallarta, Mexico
Turquoise Lake, Italy
Dead Mans Cove, Cape Disappointment State Park, Washington
Positano, Italy. How about here for a day on the beach?
Bora Bora Islands
Virgin River and Zion Canyon - Utah