A humpback whale, hopelessly tangled in heavy, abandoned fishing nets near the Farallon Islands off San Francisco, was rescued after a tense, hours-long effort by divers. The whale, unable to swim freely, was spotted by a fisherman who called for aid. 

When rescuers arrived, they realized there was only one way to save her: dive in and cut her free by hand, knowing one strike of her tail could kill them.

For hours, they worked to cut the ropes with curved blades that were wrapped around her body and mouth. 

The divers said that when she was finally free, she swam in wide circles, then came back and gently nudged each of them, one by one to let them feel her gratitude.

The diver who removed the rope from her mouth said that her eye followed him the entire time, and that he would never be the same.

"We have been given the privilege of conscious awareness, hands and bodies that have unique abilities, and a heart to take action whenever we see a person or an animal in need. Never forget how much power you have to save a life. We never know when that moment will arrive. But being prepared to want to help and take action is the first step."

(Source: National Geographic Nature)