If you've never heard of or checked out The Nature Conservancy, ladies and gentleman, now is the time. They're involved in important work all over the world, and if you love yourself some unspoiled places, it's likely that they've had a hand or at least a finger in either the preservation of that locale or the preservation of public opinion that such sanctuaries matter. In Minnesota alone, TNC has helped conserve more than 500,000 acres of wild habitat. That's no small field of grass. And the photography they post? Let's just say it's not ugly.
There are plenty of other strong organizations out there, too. Please leave a link in the comments if you think there's one in particular I need to know about!