In the 1967 Massey Lectures, Martin Luther King writes:

"Canada is not merely a neighbor to Negroes. Deep in our history of struggle for freedom Canada was the north star. The Negro slave, denied education, de-humanized, imprisoned on cruel plantations, knew that far to the north a land existed where a fugitive slave if he survived the horrors of the journey could find freedom. The legendary underground railroad started in the south and ended in Canada. The freedom road links us together. Our spirituals, now so widely admired around the world, were often codes. We sang of "heaven" that awaited us and the slave masters listened in innocence, not realizing that we were not speaking of the hereafter. Heaven was the word for Canada and the Negro sang of the hope that his escape on the underground railroad would carry him there. One of our spirituals, Follow the Drinking Gourd, in it's disguised lyrics contained directions for escape. The gourd was the big dipper, and the north star to which its handle pointed gave the celestial map that directed the flight to the Canadian border. So standing today in Canada I am linked with the history of my people and its unity with your past."