Greek/Roman architecture, specifically the temple, has had a signifigant impact on American architecture. The first thing anyone learns about Classical architecture is that there were three orders of temples, which really means that there are three kinds of pillars. The oldest and plainest is Doric. Doric pillars have tops (capitals) without any decoration, and they go straight into the ground without a seperate base. The second is Ionic, which has two swirly things (volutes) at the top which have been discribed as looking like scrolls, eyes, or seashells. It is thinner than Doric. The third order is used more often by the Romans than the Greeks, and is called Corinthian. The capitals of Corinthian pillars are very elaborate and look like they are covered with leaves (acanthus leaves, technically.)
I spent some time this year reading a translation of Vitruvius' Ten Books on Architecture (I know that sounds pretty intimitating, but the books are more chapter length than anything.) There are lots of advantages to reading about the architecture of the past from a primary source, and one main one is that they can be hilarious. Vitruvius, for example, explains the quality of different kinds of timber based on the amount of each of the four elements in the wood. We learn that fir trees have a lot of air and fire, but little water or earth. Oak has mostly earth and little of the other three. And so on. He describes how to position a town so that certain winds will not get in and make the people sick. A great deal of energy is spent, in the chapter on proportion, explaining why some people in ancient Greece/Rome think the Perfect Number is ten and some people think that it is six. See? Hilarious.
Anyway, Vitruvius has an interesting explanation of the difference between Doric and Ionic. "On finding that, in a man, the foot was one sixth the height, they applied the same principle to the column, and reared the shaft [long part] including the capital, to a height six times its thickness at its base. Thus the Doric column, as used in buildings, began to exhibit the proportions, strength, and beauty of a man. Just so afterwards, when they desired to construct a temple to Diana [goddess of hunt/moon/maidens etc] in a new style of beauty, they translated these footprints into terms characteristic of the slenderness of women [...] In the capital they placed the volutes, hanging down at the right and left like curly ringlets, and ornamented its front with cymatia [some sort of decorative motif resembling a wave] and with festoons [good word! a festoon is a garland of leaves or flowers, to festoon means to decorate. Maybe connected to festive? sorry I'm a word geek] arranged in place of hair, while they brought the flutes down the whole shaft, falling like the folds in the robes worn by matrons. Thus in the invention of two different kinds of columns, they borrowed manly beauty, naked and unadorned, for the one, and for the other the delicacy, adornment, and proportions characteristic of women." He goes on to explain how the Corinthian is supposed to be even slenderer than the Ionic, and represent a younger girl, and how supposedly the architect Callimachus got the idea when he saw the acanthus root growing on the grave of a maiden.
I think we've about wrapped up the backround discussion of Greek and Roman architecture. I don't know who's more tired at this point, the writer or the reader. So I will leave the discussion of the influence of classical temples on American houses to another time.