A green roof is a building roof that is partially or completely covered with vegetation and a growing medium, planted over a waterproof membrane. These roofs are becoming increasingly popular in urban areas for several reasons. Primarily, they offer significant environmental benefits. They can absorb rainwater, which helps manage storm water runoff and prevents flooding. In addition, the plants on green roofs help to filter pollutants from the air and reduce the urban heat island effect, a phenomenon where cities are much warmer than surrounding rural areas. There are two main types of green roofs: extensive and intensive. Extensive roofs have a thin layer of soil and are planted with light, low-maintenance plants. They are relatively inexpensive and do not require strong structural support. In contrast, intensive roofs are much deeper, like a traditional garden, and can support a wider variety of plants, including trees. However, they are more expensive and require buildings with greater structural capacity. Despite the initial cost, green roofs are a valuable tool for creating more sustainable and healthier cities.