Photo taken on Oct. 10, 2020 shows vegetation in a Tiankeng, or giant karst sinkhole, at Luoquanyan Village in Xuan'en County, Enshi Tujia and Miao Autonomous Prefecture, central China's Hubei Province. (Photo by Song Wen/Xinhua)

Photo taken on Oct. 10, 2020 shows vegetation in a Tiankeng, or giant karst sinkhole, at Luoquanyan Village in Xuan'en County, Enshi Tujia and Miao Autonomous Prefecture, central China's Hubei Province. (Photo by Song Wen/Xinhua)

Photo taken on Oct. 10, 2020 shows palm trees in a Tiankeng, or giant karst sinkhole, at Luoquanyan Village in Xuan'en County, Enshi Tujia and Miao Autonomous Prefecture, central China's Hubei Province. (Photo by Song Wen/Xinhua)

Photo taken on Oct. 10, 2020 shows palm trees in a Tiankeng, or giant karst sinkhole, at Luoquanyan Village in Xuan'en County, Enshi Tujia and Miao Autonomous Prefecture, central China's Hubei Province. (Photo by Song Wen/Xinhua)