A J-16 fighter jet of Chinese Air Force carries out flight training on June 21, the longest day of 2025. Summer Solstice has longer daylight hours and more time for flight with clear visibility, less turbulence. For pilots, it is the best time of the year to take to the skies. The summer solstice (sometimes called midsummer) is the longest day of the year. It's celebrated all around the world as a universal symbol of light, life, growth, and the prospect of a bountiful harvest in the future. (eng.chinamil.com.cn/Photo by Zhu Yunlong, Liu Qinghua and Li Fushun)