Reconstruction of the Parthenos within the Parthenon

The Parthenos stood in the Parthenon cella, facing the east door, screened at side and back with super-imposed colonnade of Doric columns.

Before it was a shallow basin of water, covering the whole floor area before the door. This provided a healthily humid atmosphere for the ivory and would have reflected light from the doorway.

She wore a small, bib-like aegis with Gorgoneion (an ivory head of Medusa) on her breast and a peplos with long overfall, tucked into the belt in a manner peculiar to the Goddess.

Pausanias describes de helmet, with a sphinx at the center and griffins in relief at either side.

She held the shield upright at her left side, with the snake coiled within it.
She held a Nike (Victory) about 4 cubits high just alighting on her hand, holding a wreath or fillet. The hand supporting the Nike was supported by a column.

Pliny says that the fight of the Lapiths and centaurs appears on (the edge of) the soles of her sandals.

On the base of the statue a relief showing the birth of Pandora. 

It is difficult, no, impossible, to assess the effect of such colossal figure, the strong verticals of the dress and support, the dazzle of gold caught in indirect or reflected light, the crisp detail of the cast and chased metal, and the ivory flesh; the contrast of the fine narrative detail on the sandals, shield and base, with the opulent simplicity of the gold dress.

Pliny says the statue was 26 cubits tall, probably around 11.5 meters.

Phidias, 438 BCE

Reconstruction after Professor Orlandos
 
Reconstruction at Ontario
 
(Click the image for a full screen view)