The latest victim of ISIS was one of Syria's top antiquities experts. Khaled al-Assad devoted his life to exploring and preserving the ancient ruins of Palmyra.
Militants who now control the city consider the relics sacrilegious, so they beheaded him and hung his body on a pole.
Al-Assad knew the risk but decided to stay because he was so involved in efforts to try to evacuate some of the precious antiquities before ISIS made its way into the city, reports CBS News correspondent Clarissa Ward.
Ward, who has done extensive reporting from Syria, says ISIS' brutality often overshadows the daily death in Syria at the hands of the Syrian regime.
A bombing in a Damascus suburb killed more than 100 on Sunday; most were civilians. The Assad regime is the only party in the war to have air power and is suspected of being behind the attack.
For more analysis on ISIS and the situation in Syria, watch the video at the top of the page.