If the Bluefin-21 sonar finds the Flight 370 wreckage authorities will likely call in high-tech equipment that is usually used in oil drilling. Rosa Flores takes a look at the subs that can be used to retrieve objects that are several miles below the ocean's surface.
Scanning the ocean floor is a slow and methodical process. Stephanie Elam got an up close look at how this is done, and the type of images investigators are working with.
Anderson Cooper goes beyond the headlines to tell stories from many points of view, so you can make up your own mind about the news. Tune in weeknights at 8 and 10 ET on CNN.
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