The Lincoln cent is the current one cent coin of the US Dollar. It was aopted in 1909, replacing the Indian head cent. Its obverse, featuring a bust of Abraham Lincoln (to commemorate his centennial), has been in continuous usage. Its reverse was changed in 1959 from a "wheat stalks" design to its current design which includes the Lincoln Memorial (to commemorate Lincoln's sesquicentennial). There are more one-cent coins produced than any other denomination, which makes the Lincoln cent a familiar item. In its life span, this coin has weathered two world conflicts, one of which changed it materially, because metals play a vital part in any war effort. The obverse is the longest design used for any circulating American design.