Lingerie Football: Super Sexy or Sexist? Players in the all-female league wear skimpy uniforms and hockey helmets. Ligers? Hybrid Cats Are Popular, Controversial Pet Descendants of lions, tigers and cheetahs, this new breed of house cat can still be wild. Manhunt for 'Christmas Cop Killer' Goes Nationwide Police are searching for the suspected bank robber who fatally shot a Mississippi police officer. Gyms for Overweight Members Only Downsize Gym only admits people with more than 50 pounds to lose. Trapped Cruise Ship Blinded by Blizzard in Antarctic Stranded crew members and passengers are waiting to be freed by icebreaker ships. LA Motorist Pulled From Burning Vehicle Off-duty police officer Don Thompson rescues man from burning car. Tracking Elusive Narwhals in the Arctic Part 1: These creatures known as the "unicorns of the sea" are threatened by climate change. Close Call on the Arctic's Melting Sea Ice Part 2: A desperate scramble over a massive crack in the sea ice creates a scary situation. Climate Change Threatens Arctic Life Part 3: Warming global temperatures are melting critical sea ice. Remote Area Medical: Serving the Underserved Part 1: "Nightline" spent time with the all-volunteer health care team in Wise County, Va. Mobile Free Clinic Helps Thousands in 72 Hours Part 2: Patient walked 15 miles to receive medical care, when doctors discover something. Capturing Unexpected Animal Behaviors Nat Geo WILD's series, "One Life," provides a different perspective on the animal world.