In Boston, Massachusetts, a plaque titled “Crossing the Bowl of Tears” remembers those who braved the Atlantic to escape death during the catastrophic Irish potato famine of the late 1840s. More than a million people died in that disaster, while another million or more abandoned home to cross the ocean, which John Boyle O’Reilly poetically called “a bowl of tears.” Driven by hunger and heartache, these travelers sought some measure of hope during desperate times...