Oprah Winfrey visits California's Pelican Bay State Prison -- where she reports on the use of solitary confinement. There's a conservative effort to protect rhinos from poachers -- who are being targeted for their horns. Lara Logan introduces us to South African rancher John Hume -- who has his own way of savings the rhinos. After 28 years in space, the Hubble Space Telescope is sending back some of its most beautiful and revealing images from across the vast universe. Bill Whitaker reports.  Learn more about your ad choices. Visit megaphone.fm/adchoices