Every spring, visitors gathering outside Stockholm’s Royal Palace witness an unusual spectacle as thousands of young fish pour into the city’s waterways through large pipes. At first glance, the event resembles a public celebration, but behind it lies a decades-long conservation programme aimed at protecting one of Sweden’s most important urban ecosystems. The annual release…

Spanish endurance athlete and mountaineer Beatriz Flamini spent 500 days alone inside a cave 230 feet beneath the Earth’s surface without sunlight, clocks or direct human contact, all in the name of science. The unprecedented experiment was designed to understand how prolonged isolation affects the human brain, body and perception of time. Cut off from…