Researchers have found that spending time in nature significantly alters the brain, with researchers reviewing over 100 studies finding that it can double your attention span, decrease negative thoughts and increase happiness, reduce physical signs of stress, and improve productivity. The study also revealed that The Spheres, a series of glass domes housing a full-blown botanical garden, was the centerpiece of Amazon's $4 billion project to build a new corporate campus in Seattle. The company declined to disclose how much it spent on the buildings and the plants, but local media reported that planning estimates put the cost at around $250 million.