Did you know that the Titanic had 2 nearly identical sister ships?

NOVA searches for great stories from the past...a B-29, on a secret reconnaissance mission over Russia, makes an emergency landing in Greenland. Pilot Darryl and his team rush to refurbish the plane before the harsh winter sets in. The second half of NOVA focuses on the Titanic's 2 sister ships, the Brittanic. Few people realize that the Titanic had two nearly identical sister ships, the Olympic and the Britannic. The Olympic had a successful career as a liner until she broke up in 1935, but the Britannic met a fate almost as unlucky as the Titanic's. Serving as a hospital ship in the Aegean, it was either torpedoed or struck a mine on November 21, 1916, and sank within an hour, yet only thirty of the crew of 1,100 died. Nova joins the search for the wreck of the Britannic and explores the evidence of its dramatic end. NOVA: B-29 FROZEN IN TIME...9pm