Ever notice how a heatwave makes you lose focus and feel incredibly stressed? When summer temperatures spike, concrete jungles turn into giant ovens. Thanks to the urban heat island effect, cities can become as much as 12° hotter than surrounding rural areas, leading to lower productivity and a massive toll on our mental health. To combat this, city planners are turning to the 3-30-300 rule: ensuring everyone can see 3 trees from their home, live in a neighborhood with 30% tree canopy cover, and stay within 300 meters of a quality green space. But what actually happens to our brains when we look at nature during a heatwave? Can green walls make you happier? Or even simply looking at green?