NASA @NASA
Ever wanted to walk in the footsteps of Lewis & Clark? We’re teaming up w/ the @NatlParkService to challenge you to navigate the trail & map land cover w/ a smart phone. You’ll be retracing the past & helping us study environmental changes! Get started: https://t.co/OKkDRrQ0G0 https://t.co/BNzMlAsI9l — PolitiTweet.org