for our series race matters, i sat down with national geographic explorer and writer tarra roberts who has been travelling the world documenting these underwater wrecks and the intrepid group of primarily black divers working to uncover them. she tells these untold stories. in her memoir written in the waters. ng us. your journey took you across four continents but you got the idea for the project that became the book here in washington, d.c. tell us about that. >> this was in 2016 and i got offered tickets to go and visit the national museum of african american history and culture, and it was there that my life completely changed. i saw a picture of a group of primarily black women in wet suits on a boat. i had never seen a picture of black women in wet suits on a boat before. i discovered that they were part of this group called diving with a purpose and that they spend their time searching for and documenting slave ship wrecks around the world. and that just, it floored me. it made me want to be a part of that work in some kind of way. >> when did you realize that your story and the