Gina McCarthy says toxic waste from last week's spill at the Gold King Mine is gone from water samples. But experts point to the contaminants that can still be stirred up from the riverbeds.
Some 30,000 African elephants die each year as a result of poaching. Journalist Bryan Christy wanted to see where their tusks were going, so he ordered fake tusks and fitted them with trackers.
Octopuses are cool. They can regrow lost arms, change the color of their skin, and are surprisingly smart. Scientists who sequenced the first octopus genome say it's nearly as big as a person's.
Nicholas Reeves studied laser scans of King Tutankhamen's tomb. He saw what he thinks are clues about other chambers hidden behind gilded frescoes that decorate the tomb.