Kentucky joined the Union in 1792, as only the second state after the original 13 colonies. Called the 'Bluegrass State,' it is home to the country's most active coal field, as well as Mammoth Cave National Park, the world's lengthiest cave system. The state also has the highest per-capita populations of deer and turkey in America. Other things the state is known for include college basketball, bourbon, and horse racing. Over 147 million gold ounces are stored at the United States Mint's depository of bullion in Fort Knox.