next few weeks to a change of regime in egypt. let's listen a little bit to the atmosphere coming from tahrir square right now. we're going to continue to follow this story with our team of reporters. ivan watson, frederik pleitgen, arwa damon and others all following the latest developments. wolf, back to you. >> thanks very much. i want to bring in an expert right now. nick burns is joining us once again. he's at the kennedy school at harvard university and nick is familiar to our viewers. he's retired u.s. state department official, former undersecretary of state. nick, talk a little bit about what the challenges are for the