The Parthenon was a temple to Athena built on top of the highest hill in Athens, the Acropolis (Acropolis means High City). In the Late Bronze Age, about 1300 BC, the Acropolis had been where the kings of Athens lived (likeTheseus in the myth), and where everybody went to defend themselves when there was a war. But after the Dark Ages, the Athenians had no more kings to rule them. Instead they had an oligarchy, and so there was no king to live on the Acropolis. Instead, the Acropolis became sacred to the goddess Athena, and the Athenians built her a temple there.
There was at least one Parthenon temple on that spot before the one that is there now. The earlier temple was built in the Archaic period out of limestone. The Persians destroyed this first temple when they sacked Athens in the Persian Wars, just before the battle of Salamis in 480 BC. We have only scraps of that temple that the priests buried on the Acropolis after the war.
For a long time after the Persian Wars, the Athenians left the Acropolis in ruins, as a sort of war memorial. But by the 440s BC, a generation later, the Athenians wanted to rebuild their Parthenon bigger and better than before.
The Athenians hired two great architects, Callicrates and Ictinus, and a great sculptor, Pheidias, to rebuild the Parthenon. This time the whole building would be made of marble, and in the very latest style, and big, too.
Learn by doing: build a model of the Parthenon in Lego or on Minecraft
Go on to the Parthenon’s Optical Illusions
A Greek Temple, by Fiona MacDonald, Mark Bergin (2002) (this is specifically about the Parthenon, not just any Greek temple)
Parthenon, by Lynn Curlee (2004). Easy reading. Lovely pictures.
The Athenian Acropolis: History, Mythology, and Archaeology from the Neolithic Era to the Present, by Jeffrey M. Hurwit (2000). This is not so easy, but it is pretty interesting reading. Hurwit is a archaeologist and art historian who works on the Athenian Acropolis.