Workers clear the rubbish in a Tiankeng, a Karst landform, at Luoquanyan Village of Xuan'en County, central China's Hubei Province, May 15, 2015. Dozens of workers started to clear the rubbish out of the over 290-meter-deep Tiankeng, which was used as a refuse dump, since January this year. A local enterprise invests several million yuan on the rubbish clearance with an aim to restore the ecological system in the Tiankeng and to develop it into an integrated scenic spot of expedition, leisure and geologic sightseeing. (Xinhua/Song Wen)