Ever since the 15th century, with the race to find a route to Asia, European men began to explore the world around them outside the limits and frontiers of the European continent; from Africa to the Indian sub-continent, from the Americas to the Middle East, and finally to Asia. Today, there is no unchartered piece of land, no terra incognita, that man has not set foot on. The mysteries of the earth have been laid bare, or so we think. Thankfully, there is still one last final frontier: The oceans. The ocean covers 71% of the Earth’s surface and contains 97% of the planet’s water, yet more than 95% of the underwater world remains unexplored. From past underwater findings we know the oceans are a vast reservoir of treasures and secrets. Underwater explorers have discovered lost kingdoms, fathomless canyons and mysterious objects. What else is down there? Here are 20 amazing underwater discoveries.