via Lisa Miller 

Originally shared by National Geographic

We're bringing together Robert Ballard, James Cameron, Jane Goodall and explorers from all seven continents.

Use #NatGeo125 to ask questions here or on YouTube and tune in to the Hangout on Air this Sunday, January 13 at 1 p.m. ET (6 p.m. UTC). http://on.natgeo.com/WEBZcd