Collectible coins refer to items that are valued for their rarity, historical significance, or unique features. In the United States, one notable collectible is the 1947 Denver Mint cent, commonly known as the Lincoln penny. This coin is part of the series minted since 1909 and features President Abraham Lincoln on the obverse and the Lincoln Memorial on the reverse. The 1 cent denomination, often found in rolls, can vary in value based on condition, demand, and any unique minting characteristics.