Allentown is the largest city in the Lehigh Valley, with a downtown that has seen new life in recent years. The Allentown Art Museum holds American art and a library of works on paper, while the Da Vinci Science Center offers hands on science exhibits nearby. The PPL Center downtown hosts hockey, concerts, and events, and America on Wheels Museum celebrates transportation history. Allentown also has a famous Liberty Bell connection: during the Revolutionary War, the Liberty Bell was hidden in the city to protect it from British forces. The Lehigh Valley region around Allentown mixes industry, farms, and small towns.