This global challenge invites people to document the wild side of their cities

California started this community project to document urban nature | The City Nature Challenge is an annual contest to document as many species of plant, animal and other types of critters in a four-day period. This year’s event begins Friday and closes on Monday. It include 488 cities worldwide.

UAE releases stunning images of Deimos, Mars' smaller moon, that could challenge a long-standing theory

Chemists tackle the tough challenge of recycling mixed plastics