From the frozen ice caps of the polar regions to the warm waters of the tropical coral reefs, from deep sea vents to shallow seagrass beds, the oceans contain the greatest diversity of life on Earth.

Reusable coffee cups from Chilly’s, KeepCup, Frank Green and more were also put through their paces, and again we found two Best Buys. Discover the best travel mugs below, or scroll down for the best ...