A Titanic expert, an adventurer, and a father and son are among the passengers on missing sub

A renowned Titanic expert, a world-record holding adventurer and two members of one of Pakistan’s wealthiest families are facing critical danger aboard a small submersible that went missing Sunday while descending to the world’s most famous shipwreck. The race is now on to find the Titan, which has an oxygen supply that is expected to run out at about 6 a.m. Thursday. The people on board include British businessman and world-record holding adventurer Hamish Harding; Titanic expert Paul-Henry Nargeolet, who has made multiple trips to the wreck; and businessman Shahzada Dawood and his son Suleman.