People now live and work in high-rise buildings which depend on artificial energy sources like electricity. In the natural world, insects like spiders use a saliva-made fibre to construct their steely web. Termites build intricate airway systems in their habitat. In the same way, some architects and engineers have turned to nature for inspiration when designing buildings. These are called bionic buildings. They are designed to enhance the efficiency in usage of energy by having a provision for entry of sunrays to reduce dependence on electricity.