FRED PLEITGEN, CNN CORRESPONDENT: That started three years ago, and the Syrian observatory for human rights says at least 150,000 people have been killed, and that roughly a third of those people are civilians. A week ago, a truce took effect in the city of Homs. This is a strategically important city for both the Syrian government and the rebels fighting it. It`s an ancient city, and it`s a city that`s been under siege in the conflict.