The bald eagle, a symbol of freedom and strength, faced a difficult past. Just a few decades ago, these birds were vanishing. In the 1960s, only around 417 nesting pairs of bald eagles could be found across America's lower 48 states. A harmful pesticide called DDT was making them sick. It weakened their eggshells, causing chicks to die before they could even hatch. But America wouldn't give up on its symbol. Scientists discovered the danger of DDT and people took action. Thanks to the Endangered Species Act and a ban on DDT, bald eagle populations soared. Today, thanks to continued protections, there are over 71,400 nesting pairs of bald eagles in the lower 48 states.