The Top 10 Everything of 2010

It was the heartbreaking story heard 'round the Internet — a beloved giant panda, living in China's Jinan Zoo, died after accidentally being gassed with carbon monoxide and chlorine. An autopsy revealed that the 21-year-old panda, Quan Quan, inhaled the gases that were being used to disinfect a nearby former air raid shelter. Zoo officials said that the gases had filtered through ventilation pipes the zoo shares with the raid shelter. The toxic gases caused the panda's lungs to collapse; despite attempts to save her, Quan Quan died in the hospital.

Activists quickly pointed to Quan Quan's death as yet another indication of how zoos should improve their treatment of animals in captivity, while others criticized the practice of keeping pandas in captivity at all (she wasn't the first panda to die in a zoo — her death actually marked the second for the Jinan Zoo). A national symbol of pride in China, giant pandas are an endangered species and Quan Quan's death was mourned throughout the country.