When Doug Tompkins wants to drop in on his neighbor, the best way to do so -- in fact, the only way to do so -- is to fire up his Cessna 206 and fly across the vast subtropical wetlands that he owns in this remote corner of northeastern Argentina.

CNN: The story

While the Tompkins are heroes in most environmental circles, some activists and political leaders have labeled Doug as arrogant, eccentric and out-of-touch with the pressing needs of humans.

CNN: The philanthropists 'paying rent' to planet Earth in Argentina