Today, in our series on urban planning, we're looking at how cities can become more sustainable. One key aspect is the use of green roofs. These are rooftops covered with vegetation, which help to insulate buildings, reducing energy costs by up to 25% in summer. Additionally, they absorb rainwater, decreasing the risk of flooding. However, the initial installation cost is high, and maintenance requires regular attention. Some cities, like Toronto, have introduced bylaws encouraging green roofs on new buildings. Despite the benefits, many developers hesitate due to the upfront expense.