At the beginning of April, Google announced a new default layer for oceans in Google Earth.
The new oceans layer includes hundreds of sites generated from data, images, and videos from organizations like National Geographic, NOAA, and dozens of others.
National Geographic ocean explorer, Sylvia Earle, narrates a highlight tour through some of the best photos and videos in the 'Explore the Ocean' layer in Google Earth : -> GE Explore-oceans
In the same announcement, Google featured a new narrated tour called Hope Spots in the Ocean Showcase which displays eight places around the world considered to be indicative of the health of the world's oceans and marine life.
Take a tour with Mission Blue : -> GE_Hope-spots