This house by Deca Architecture is a building built into it's surrounding topography. This is a great building to look at for this project, especially regarding the underground section of the brief. Perhaps the most interesting part of the design is the way in which light is allowed down into it.
Furthermore, the concept of green roofs is also very interesting to me, they are very insulating, absorb water, work with the environment and are generally beneficial. I will look into them further, but I have a great interest in including them within my own design. It is worth bring in mind that green roofs are heavy though and may require stronger supports.