Canada is celebrating Emancipation Day, the anniversary of the Aug. 1, 1833, Slavery Abolition Act, which abolished slavery in most of the British Empire in 1834. Though informally celebrated for generations, the occasion has only recently become a federal holiday in the country. In doing so, the holiday highlights the little-known history of slavery in Canada and has stirred up calls for greater efforts to address the lingering effects of such oppression.