Photo taken on April 28, 2019 shows a yak resting at Gyirong county of Xigaze city, southwest China's Tibet autonomous region.The vast drop in altitude in Gyirong county, known as the "backyard garden of Mount Qomolangma", makes the ecological environment unique, with crystal-clear lakes and towering mountain peaks creating a mesmerizing scene. Mount Qomolangma is known as Mouth Everest in the West.[Photo/Xinhua]

The vast drop in altitude in Gyirong county, known as the "backyard garden of Mount Qomolangma", makes the ecological environment unique, with crystal-clear lakes and towering mountain peaks creating a mesmerizing scene. Mount Qomolangma is known as Mouth Everest in the West. [Photo/Xinhua]

Photo taken on April 28, 2019 shows the scenery in Gyirong county of Xigaze city, southwest China's Tibet autonomous region.The vast drop in altitude in Gyirong county, known as the "backyard garden of Mount Qomolangma", makes the ecological environment unique, with crystal-clear lakes and towering mountain peaks creating a mesmerizing scene. Mount Qomolangma is known as Mouth Everest in the West. [Photo/Xinhua]

A view of the canyon scenery in Gyirong county of Xigaze city, southwest China's Tibet autonomous region on April 28, 2019. The vast drop in altitude in Gyirong county, known as the "backyard garden of Mount Qomolangma", makes the ecological environment unique, with crystal-clear lakes and towering mountain peaks creating a mesmerizing scene. Mount Qomolangma is known as Mouth Everest in the West. [Photo/Xinhua]

Photo taken on April 28, 2019 shows a woman working at Naicun village in Gyirong county of Xigaze city, southwest China's Tibet autonomous region.The vast drop in altitude in Gyirong county, known as the "backyard garden of Mount Qomolangma", makes the ecological environment unique, with crystal-clear lakes and towering mountain peaks creating a mesmerizing scene. Mount Qomolangma is known as Mouth Everest in the West.[Photo/Xinhua]

The vast drop in altitude in Gyirong county, known as the "backyard garden of Mount Qomolangma", makes the ecological environment unique, with crystal-clear lakes and towering mountain peaks creating a mesmerizing scene. Mount Qomolangma is known as Mouth Everest in the West. [Photo/Xinhua]