Videos of Islamic State militants shattering ancient statues and blowing up classical temples have shocked the world. But according to a new analysis of satellite images by U.S. archaeologists, these high-profile acts obscure the actual extent of damage to Syria’s rich cultural heritage.

The team examined images of 1,450 ancient sites across the shattered nation and found that one in four has been damaged or looted in the civil war that began in 2011.