The scale of poaching is a criminal horror. Why Obama should make it a priority issue -- in his meeting with China's Xi Jinping this week and beyond

Certain substances produced by the human brain and pituitary gland may lead to new treatment for mitigating pain, curing drug addiction, and healing mental illness. In several laboratories in the United States and Europe, scientists are excitedly competing to duplicate the opiatelike material and apply it to a broad range of human ills.

In the spirit of celebrating, rather than ranking, our eclectic mix of content, here is a selection of standout videos in no particular order