It's not easy to swim with sperm whales: they're hard to find, hard to reach without adequate diving experience, and they just might swallow you up if you get too close. But how else are we going to crack their complicated language system? A group of rogue freedivers takes the plunge.
You're ready to act on those good intentions, but how do you know the organizations you're backing deserve your trust? Here are the 30 best—smartly managed groups with transparent financials, efficient spending, and track records of on-the-ground success.