<human>:  What is the significance of the "Golden Mean" in classical architecture?
<bot>: The "Golden Mean" is a principle of classical architecture that stated that the proportions of a room or structure should be proportionate, with no part of the structure being too large or too small in relation to the rest. This principle was seen as aesthetically pleasing and was used in many classical architectural works. It is known as the Golden Mean due to the fact that the ratio is approximated by the Greek letter Phi, which is 0.618 and is known as the Golden Ratio.