Almost three miles of ice buries most of Antarctica, cloaking a continent half again as large as the United States. 

But when an Antarctic ice shelf the size of Manhattan collapsed in less than a month in 2002, it shocked scientists and raised the alarming possibility that Antarctica may be headed for a meltdown.  Even a 10 percent loss of Antarctica's ice would cause catastrophic flooding of coastal cities unlike any seen before in human history.

What are the chances of a widespread melt?  NOVA: SECRETS BENEATH THE ICE explores whether Antarctica's climate past can offer clues to what may happen.

NOVA follows a state-of-the-art expedition that is drilling three-quarters of a mile into the Antarctic seafloor.  The drill is recovering rock cores that reveal intimate details of climate and fauna from a time in the distant past when the Earth was just a few degrees warmer than it is today.

As researchers grapple with the harshest conditions on the planet, they discover astonishing new clues about Antarctica's past — clues that carry ominous implications for coastal cities around the globe.