The Freedom From Religion Foundation placed "Praise Darwin" billboards in Grand Junction; Dayton, Tenn.; Dover, Pa.; and Whitehall, Ohio.
They feature stained-glass designs and a picture of the evolutionary theorist born on Feb. 12, 1809.
The Tennessee and Pennsylvania towns had landmark court cases about the teaching of evolution.
In Grand Junction, the foundation has complained about prayers in county meetings. The organization has battled Whitehall over nativity displays.
The Wisconsin-based foundation is made up of agnostics and atheists opposed to government displays of religion.
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