president obama has left afghanistan after his surprise visit to u.s. troops there today. he made the trip to thank the troops for their service on this memorial day weekend. and he said progress in the region is noticeable. >> al qaeda is on its heels in this part of the world and that's because of you. we said that that we were going to reverse the taliban's momentum. and so you went on the offense driving the taliban out of its strongholds. look. everybody knows afghanistan's still a very dangerous place. insurgent still launch cowardly attacks against innocent civilians but just look at the progress that you've made possible. afghans reclaiming their communities and more girls returning to schools. dramatic improvements in life expectancy and literacy. that's your legacy. >> u.s. troops have been fighting in afghanistan for more