April 24 marks the Space Day of China, and on this occasion, the "Lunar Palace 1" base at Beihang University in Beijing was opened to the public, attracting numerous space enthusiasts to visit. The "Lunar Palace 1" is a ground-based integrated bioregenerative life support system (BLSS) facility, developed under the leadership of Professor Liu Hong from the university. It represents the world's first successful four-component artificial closed ecosystem (human-plant-animal-microorganism) and has completed the world's longest-duration and highest-closure human survival experiment. Photos: Chen Tao/GT