A few of several years ago, Alec Soth, the great street-tripping witness of American daily life, made a decision to retrace the route of the most popular funeral procession in his nation’s heritage: the educate journey that carried assassinated President Lincoln’s 6ft 4in corpse from Washington DC to his property town of Springfield, Illinois. The steam-run cortege was witnessed by tens of millions of Individuals, among the them the poet Walt Whitman, who was moved to create his elegy, When Lilacs Past in the Dooryard Bloom’d. Soth set out on his journey with a line from Whitman’s poem in his head – “And what shall the photos be that I…