- Mosul Dam was built in the mid-1980s on soft gypsum rock, which is constantly eroding
- U.S. experts warn the dam is at risk of "catastrophic failure." If it breaks, 1.5 million people could be at risk
- Workers pump about 2 tons of concrete into boreholes in the dam's foundations every day to shore it up
Mosul Dam, Iraq (CNN)Only one of the two bottom outlet gates is functioning, angrily spitting out water in a foamy white churn as birds fly above the spray.