(250421) -- BEIJING, April 21, 2025 (Xinhua) -- This photo taken on Jan. 2, 2025 shows untethered terrestrial-aerial micro-robots developed by a research team from Tsinghua University, in Beijing, capital of China. TO GO WITH "China Focus: Chinese scientists develop world's smallest untethered terrestrial-aerial micro-robot" (Tsinghua University/Handout via Xinhua)