The next time you take an elevator to the top floor of a big city skyscraper, you might be in for a surprise – especially when you see tall green grass, wildflowers, and even butterflies fluttering about their business. And the reason for this high-rise nature wonderland is that many office buildings are developing what are called “green roofs” – meaning roofs that contain various growing plants laid out in trays containing six inches of soil. The advantages of green roofs are that they reduce cooling and heating costs, last about 40 years, help reduce water drainage, and of course look beautiful. With the number of green roofs growing by some seventy percent last year in the U.S., maybe city folk can also now enjoy mowing the lawn.