December - Amazon deforestation drops by 31% - The rare pink pigeon species has been saved - Extinct snails are thriving ...

The global population is growing, but do you know which city is biggest? These are the most populated cities in the world.

Champaign's Jen Setser, Stacy Baby, Emma Delgado, Ryley Edmonson and Valerie Prescott; Urbana's LeKisha Hall and Cindy Adamek ...