Greek Temples and Columns ~~ Doric, Ionian, and Corinthian
In addition to the three commonly identified styles of columns - doric, ionian, corinthian - you will notice in the pictures below that some columns, in particular the "capitols" of the columns demonstrate characteristics of more than one style. As is true in most artistic fields, styles were continually evolving and sculptors, more accurately, "schools" of sculpture frequently introduced innovations into their designs to distinguish themselves from other sculptors and schools.
Rather amazingly. considering both their antiquity and the aerial bombing that occurred during World War II, most of these sites in Greece can still be visited today. The Parthenon which crowns the Acroplis in Athens is the one temple every visitor to Greece hopes to see, but I have a recommendation.
If, on your excursion to Greece you only have time to visit one temple (and God forbid that should be so), I recommend the temple built to the god of the sea, Poseidon (Neptune if you prefer the Roman nomenclature) at Sounion. Not much of the original temple remains, but the ruins - a few columns are situated atop a sheer bluff that falls away in a dramatic drop hundreds of feet down to the rocks.
The rocks which the Aegean Sea has been pounding against and slowly weathering away from time immemorial. And depending on the time of day or season of the year, the Aegean will be aquamarine, deep blue, or perhaps even violet. And on the horizon out to sea will appear the dim outlines of other Greek islands.