Read this: Philadelphia is home to many national historical sites that relate to the founding of the United States. Independence National Historical Park is the center of these historical landmarks being one of the country's 22 UNESCO World Heritage Sites. Independence Hall, where the Declaration of Independence was signed, and the Liberty Bell are the city's most famous attractions. Other historic sites include homes for Edgar Allan Poe, Betsy Ross, and Thaddeus Kosciuszko, early government buildings like the First and Second Banks of the United States, Fort Mifflin, and the Gloria Dei (Old Swedes') Church. Philadelphia alone has 67 National Historic Landmarks, the third most of any city in the country.
Now answer this question, if there is an answer (If it cannot be answered, return "unanswerable"): How many UNESCO sites does the U.S. have?
22 UNESCO World Heritage Sites