revision preference src: They were the only two people to do this until March 26, 2012, when James Cameron reached the bottom. <SEP> It has been reported that Don Walsh was on the team that oversaw James ' journey. <SEP> tgt: Walsh joined the team that oversaw the dive of the " Deepsea Challenger " mission where James Cameron dove solo to the bottom of the Mariana Trench on March 26, 2012.