海底大揭秘第四季　　Combining undersea exploration with innovative visualizations, DRAIN THE OCEANS reveals hidden evidence of amazing undersea mysteries.　　Not “artists impressions” but what is actually there — down to the very last rivet. And, for its fourth season, it embraces a gripping new style, telling stories purely through the words of explorers and archaeologists, putting viewers right by their side.　　Episodes include…　　1.The Wild West　　2.The Battle for the Black Swan　　3.Arctic War　　4.Hollywood　　5.The First Americans　　6.Venice's Lost Empire　　7.The Mississippi River　　8.Hurricane Apocalypse　　9.The Great Barrier Reef　　10.Sea of Secrets