Have you ever wondered why there are around 52 cards in a deck? Well, one of the most important theories in this regard tends to talk about how cards symbolize the calendar. Yes, that’s right. Cards correspond to the number of weeks, and this is known to be a top fact. Apart from that, there are also other facts that talk about how the world’s oldest deck of cards is in NYC, how Vegas changes decks more than often, and why one card manufacturer dominates the market. Yes, you heard that right. The United States Playing Card Company (USPCC) is the biggest manufacturer of playing cards.