Filmmaker Bertie Gregory's new documentary special captures the extreme challenges facing the world's fastest land animal.

From giant stick bugs to rarely seen sea creatures, these animal videos fascinated us—and led to new scientific discoveries.

LOS ANGELES -- Commit first, then figure it out. That was one of the mantras of conservationist Doug Tompkins and his wife Kris. Their story, including the highs and lows of their biggest project, is ...