Market Street has been called the most historic highway in the United States because of the various historic sites along its eastern section. Many of Benjamin Franklin's activities were centered along Market Street. His house was located near the intersection of Fourth Street, and he may have performed his famous kite-flying experiment near Third and Market Streets. Thomas Jefferson wrote the Declaration of Independence in a boarding house (the Graff or Declaration House) once located at the Seventh Street intersection. The mansion of Robert Morris, financier of the American Revolution, was located near Sixth and Market Streets. This house, known as the President's House, was used by George Washington and John Adams as their residence during their terms as President. (The house was more or less on the site of the northern part of the modern-day Liberty Bell Center.) Around 1795 Theophilus Cazenove lived at Market Street. Several important finance and publishing firsts also occurred along Market Street between Second and Fourth Streets during the 18th century. Market Street is still one of the principal locations of business and commerce in Philadelphia.