Allbirds offers a line of sneakers, running shoes, flats, and clothing made with premium, natural materials. With a focus on sustainability, Allbirds shoes are craft with planet-friendly materials, like merino wool and eucalyptus trees. Due to their special construction, wool has many natural properties that make for amazing sneakers. They're lightweight and breathable, cool in the heat, and warm in the cold. Maybe that's why Allbirds boasts the world's most comfortable shoes.