Leaving the Airport on a Layover in China

Hi, I am an American citizen traveling to the Maldives but I have an 8 hour layover in Shanghai, I understand I DO-NOT need a visa if I'm there Less than 24 hrs. and within the Airport boundaries. My question is, would I need a Visa to leave the Airport DURING my layover and Explore Shanghai a bit before re-entering the Airport to board my connecting flight.