Story : The weather in the mountains can change suddenly and go from sultry heat to arctic cold. The higher you go, the less oxygen you have available. Nonetheless, millions of people around the world choose to live at great heights, compensating for the great difficulties of survival with technology or community spirit. The Himalayan and Andean populations are an example for all. The fascinating landscapes of the high mountains and the people who live there at dizzying altitudes in the extraordinary documentary Mountains from the BBC Human Planet series. The number of nerve cells that make up our brain is equal to that of the stars in the Milky Way: one hundred billion. Today, thanks to research, such as that conducted at the University of California in Los Angeles, it is possible to understand what happens in the brain when you use the many and different drugs, which unfortunately are in circulation.