Lucky Loonie
From Halopedia, the Halo wiki
The Lucky Loonie is an Easter Egg located in the Halo 3 multiplayer map Snowbound. In the Active Camo tunnel, there is a Canadian $1 coin (or loonie) buried in the snow beneath the Active Camo, perhaps a homage to the "lucky loonie" customarily buried under the ice during Canadian National ice hockey or curling events.[1] The "lucky loonie" was made famous during the 2002 Salt Lake City Olympic games when both the Canadian mens and womens teams won the gold medal. However, this coin is not seen during split-screen games.
One way to view it is to zoom in on it using a Sniper Rifle. You can also use the Pan Cam in Theater to get very close to the coin.
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