Every summer, millions of visitors flock to the monuments and memorials on the National Mall in Washington D.C. One of the country’s oldest police equestrian units, the U.S. Park Police mounted officers are responsible for keeping the nation's Capital and its visitors safe. From Presidential Inaugurations to political demonstrations, mounted officers help provide crowd control, traffic management and are goodwill ambassadors to the public. We spent a day with Officer Chester West and his horse D