The science and technology of building has allowed for much progress in the 21st Century.  Building designs are becoming more complex in nature to save costs and prove to be more sustainable in consideration of the depletion of the Earth's natural resources.  Green Building is simply building with an eye towards the protecting the environment and finding ways to conserve resources.  There is a Green Building standard set in the United States and such measures are being considered in other countries to provide uniform measurements of Green Building standards.