and that, says salopek, is just part of the plan.got g.p.s., you've got maps, you've got guides, you are still going the wrong way sometimes. >> being found is overrated. being a little lost is good because it keeps you alert, keeps you looking around. it keeps you scanning the horizons about to find your bearings and you are not sleepwalking through the world. >> sreenivasan: so how many pairs of shoes do you think you've gone through? >> this is the fourth. somebody brought me these from the states, so they're kind of special. >> sreenivasan: do you get tired by the end of an average day or has your body gotten used to this pace? >> i do. you know, it depends on my physical condition. you know the walk has kind of turned into my life, so it's a complicated question to answer. like, you have good weeks and bad weeks. i think i'm in pretty good condition, but i get tired, and my job in quotes is to write, not just to walk. so at the end of the day it takes a special effort to sit down and write a story. >> sreenivasan: those stories

." >> ifill: since january 2013, journalist paul salopek has tracked ancient man's path out of africae out of eden walk." last night, hari sreenivasan showed you the project he'll spend much of the next decade completing. tonight, hari walks with paul in the footsteps of early man, to one point of real meaning on his global trek. >> sreenivasan: the fog-shrouded fields and rolling hills of southern georgia are much more than a way-point for paul salopek. we were nearing the ancient city and archaeological site of dmanisi. >> dmanisi is finally in sight and it's probably one of the most important human migration sites outside of africa. >> sreenivasan: salopek is following the path humans took after the ice age, 70,000 to 100,000 years ago. but here in dmanisi, that path is much older. along these green and jagged river gorges, man has walked-- in one form or another-- for nearly two million years. the history here is stacked high, part of what salopek calls "the layer cake effect" of the caucasus. with a happy dog welcoming us, we passed what was likely an outer defensive tower of the

. >> ifill: also ahead this tuesday, in the footsteps of our ancestors: journalist paul salopek walksworld to uncover human's prehistoric journey. >> the walk has opened up the vista to me in both space and time where i can see the connections between all of these stories and i see how history informs everything that's happening today. >> woodruff: and "breaking bad" actor bryan cranston talks about playing a black-listed screen

paul salopek isn't trying to set a record-- he's doing it to tell the stories of the people and places he encounters along the way. and he's already logged about 4,000 miles. what's it like? you can ask him yourself, at 1:00 p.m. eastern tomorrow in our twitter chat, co-hosted with national geographic. details are on our home page. and sixty-five years after charles schulz introduced the world to charlie brown, the gang is reunited on the big screen in the form of "the peanuts movie." to celebrate, we've compiled eight things you didn't know about snoopy and the gang. that's on our home page: www.pbs.org/newshour. tune in later tonight. on charlie rose, more on the fight against isis in iraq, and efforts to reclaim a key city. and that's the newshour for tonight. i'm gwen ifill. join us on-line, and again here tomorrow evening with mark shields and michael gerson. for all of us at the pbs newshour, thank you and good night. >> major funding for the pbs newshour has been provided by: ♪ ♪ ♪ ♪ moving our economy for 160 years. bnsf, the engine that connects us. >> the lemelson foundation.