listen n. '98 he swam across the atlantic from massachusetts to france but the pacific has never been done before and for eight hours a day he'll be in water swimming more than 5,000 miles. this morning, the swimmer who already conquered the atlantic 20 years ago begins a truly unthinkable swim. the rough seas of the pacific ocean from tokyo to san francisco. overnight beginning his swim off the coast of japan and broadcasting on facebook live. >> there we go. he's starting. >> ben is starting his swim. >> reporter: ben lecomte beginning the swim side by side with his two children speaking with us just moments before taking that plunge. >> there's more than one challenge. on the top of the list you have the water. the cold water. >> reporter: lecomte's journey 5,500 miles, 6 months, 8 hours a day at a time. >> i have to eat 8,000 calories per day so if i don't eat it lose quite a bit of en i'm weig sthatll. >> rter: he fastle the pacific's rough weather,