From the Hoover Dam in Arizona to the Inguri Dam in Georgia, many of the world s most famous dams are risk of collapsing, a worrying new report has warned.
Most of the 58,700 largest dams worldwide were constructed between the 1930s and 1970s, making them between 50 and 90 years old.
However, most were only designed to last for 50 to 100 years, meaning they are now reaching the end of their lifespans.
Worryingly, if these dams did collapse, they d release up to 8,300 cubic kilometres of water - enough to fill the Grand Canyon twice over.
The researchers hope the findings will help policymakers when deciding what to do about ageing dams.