PBS News Miles O’Brien and his team have joined a group of scientists, engineers and researchers on a voyage to reach the famous Thwaites glacier — a chunk of Antarctic ice the size of Florida that scientists fear could someday collapse and dramatically raise sea levels. Miles paid a visit to the surface of the glacier where the team will drill through 3,000 feet of ice to reach and study the Amundsen Sea below. Join Miles for a quick -- and frigid -- tour. | PBS NewsHour