ERBIL, Northern Iraq - When ISIS captured the Mosul Dam, Iraq's largest, less than two weeks ago, experts warned the consequences could have been catastophic.
It's not just that ISIS could blow up the dam or that it could be destroyed in the middle of this battle. The dam is so fragile, it needs constant maintenance to keep it from bursting.
The U.S. Army Corps of Engineers once called it "the most dangerous dam in the world."
If it burst, experts say it would send a wall of water 60 feet high rushing downstream towards Mosul and Baghdad. It's estimated it would kill as many as 500,000 to 600,000 Iraqis.
Watch how far the water would reach if the Mosul Dam broke.
Recapturing the dam is a significant victory for the Peshmerga, or Kurdish fighters.
"This is our observation point, the last point facing ISIS controlled regions. Our duty is to control this community and this area," a Peshmerga officer said.
U.S. airstrikes played a key role in the offensive. The Pentagon announced the military hit a number of ISIS positions near the dam.
Local officials say U.S. involvement in the battle against ISIS is invaluable.
"Every single person in the region, we appreciate that because it changed many things," Erbil Gov. Nawzad Mawlood said. "Very important to support us because we haven't such a capability to stand against these people alone."
Some U.S. lawmakers are calling on the Obama administration for an even greater military response to ISIS.
"Frankly, we need to do everything we can to repel ISIS. I don't think we have the luxury of putting our heads in the sand and saying, 'Well, it's over there and we're not going to do it,'" Rep. Elliot Engel, D-N.Y., said. "I think what we're doing now is effective and we are going to do more of it, and ultimately we may have some boots on the ground there."
"Unfortunately, President Obama bugged out of Iraq, and that was a strategic and historic blunder and we're seeing the results of that," Sen. Ron Johnson, R-Wis., said. "So, right now, what the president has to do is he has to assemble a coalition of the willing."
The United States might find a willing partner in British Prime Minister David Cameron, who warned against the poisonous influence of ISIS in Great Britain.
In the meantime, ISIS continued its murderous rampage throughout northern Iraq with another massacre, this time in the village of Kocho that followed a gruesome, barbaric, and predictable ISIS pattern.
"They separated women and children from the men. They put women and children in a hall and put the men on another side," Nayef Jassem, a Kurdish relative of the victims in Kocho village, said. "They took their IDs, gold, properties."
"Then they took the men, group by group and took them outside of the village by cars, and killed them until no men were left in the village," he continued. "Then they took the women by cars somewhere towards Shingal (Sinjar). I don't know where they took them."
ISIS gave the residents of Kocho a deadline to convert to Islam. They gathered the villagers in a school and promised they could leave.
They then began to murder.
Tens of thousands of Yazidis have already fled the ISIS rampage and found refuge in a number of U.N. refugee camps.
ISIS targets minorities like the Yazidis and Christians in its grisly drive to establish an Islamic state in the middle of the Middle East.