Although I was in transit myself yesterday, I have heard from many people they were able to catch 60 Minutes last night and learn about some discoveries E/V Nautilus made in the 2014 expedition season, in the Gulf of Mexico.
Check out the blog piece here written about the identity of an unknown shipwreck which was revealed last summer and featured last night on 60 Minutes.
There’s a great video also as the team views the shipwreck for the first time.
By the way, the answer is half the country lies under the sea AND is unexplored. See NOAA’s detailed explanation of what an exclusive economic zone is and how the US’s zone was established in 1983 by President Ronald Regan.