China's self-developed Haiqin, a 6,000-meter deep-sea remotely operated vehicle (ROV), is recovered from the sea from the Zhong Shan Da Xue vessel, in the South China Sea on August 23, 2025. The electric ROV system, designed and built by Shanghai Jiao Tong University, reached a depth of 4,140 meters during the sea trial. Photo: courtesy of Sun Yat-sen University