Hot air balloons glide across the Danxia landform during the first hot air balloon festival in Zhangye, Northwest China's Gansu province, July 20, 2019. The unique Danxia landform in Zhangye features multicolored ridges of weathered strata. Visitors can not only marvel at the natural wonders here, but also can try hot air balloons, helicopters and powered parachutes.[Photo/VCG]