This paper presents a design report on a humanistically-informed data visualization of a dataset related to the trans-Atlantic slave trade. The visualization employs a quantitative dataset of slaving voyages that took place between 1565 and 1858 and uses historical scholarship and humanistic theory in order to call attention to the people behind the data, as well as to what the data does not or cannot represent. In the paper, we summarize the intersecting histories of slavery and data and then outline the theories that inform our design: of the archive of slavery, of the dangers of restaging historical violence, and of visibility, opacity, representation, and resistance. We then describe our design approach and discuss the visualization's ability to honor the lives of the enslaved by calling attention to their acts of resistance, both recorded and unrecorded.