Prove it.
Evening + Morning = ONE DAY
Many want to consider the days in Genesis one as metaphorical or symbolic. However, there is nothing in the text to suggest this. The evening and morning gives each day a distinct boundary.
The terms “evening” (Heb., ereb) and “morning” (Heb., boqer) occur more than a hundred times in the Old Testament and ALWAYS have literal meaning, that is, the termination of the daily period of light and the daily period of darkness, respectively. Also, in the Pentateuch, the occurrence of “day” modified by a numeral (i.e., third day), which appears more than a hundred times in it, is always presented as its literal meaning.
http://www.biblicist.org/bible/light.shtml