Boys and girls spontaneously formed Scout troops and the Scouting Movement started spontaneously, first as a national, and soon an international phenomenon. A rally of Scouts was held at Crystal Palace in London in 1909, at which Baden-Powell met some of the first Girl Scouts. The Girl Guides were subsequently formed in 1910 under the auspices of Baden-Powell's sister, Agnes Baden-Powell. In 1912, Baden-Powell started a world tour with a voyage to the Caribbean. Another passenger was Juliette Gordon Low, an American who had been running a Guide Company in Scotland, and was returning to the U.S.A. Baden-Powell encouraged her to found the Girl Scouts of the USA.