The famous bald eagle, the U.S. national symbol, was chosen for its physical strength, fierce beauty, and independence. (See "Endangered No Longer: Our Favorite Pictures of Bald Eagles.")
But the original design included another species: An imperial eagle, which is native to southeastern Europe.
It's an important reminder that more than 60 species of eagles live worldwide in every continent but Antarctica. In fact, only two eagle species live in North America—the bald eagle and the golden eagle, which is the national bird of Mexico.
Not every species has the fortune of being a national icon, and many are still at risk of extinction.
The Spanish imperial eagle of the Iberian Peninsula and the Steller's sea eagle of Russia and parts of Asia are both listed as vulnerable by the International Union for Conservation of Nature. There are fewer than 5,000 Steller's sea eagles left on Earth, having declined due to pesticides, overfishing, and human development.
Eagles around the world—including the bald eagle—are threatened by ingesting animals which have been shot by lead bullets.
Not all eagles are imperiled, however. The white-tailed, or sea, eagle, has bounced back in Europe after countries banned the pesticide DDT and industrial chemicals known as PCBs. There are now more than 24,000 in the wild—and they may be posing a new threat to other at-risk birds.
The power and hunting skills of many of these eagle species is impressive. The crowned eagle, considered the most powerful eagle species in Africa, can kill animals more than four times their size. The harpy eagle of South America has five-inch, curling rear claws—larger than grizzly bear claws.
In honor of Save the Eagles Day, which occurs annually on January 10, we put together our favorite pictures of the eagles you may not have heard of.