Search for Shackleton ship starts

Antarctic scientists seeking to locate the wreck of Sir Ernest Shackleton's lost ship, the Endurance, have arrived at the search site. The team broke through thick pack ice on Sunday to reach the vessel's last known position in the Weddell Sea. Robotic submersibles will now spend the next few days scouring the ocean floor for the maritime icon. Prof Julian Dowdeswell explained the search plan.