This month marks the 150th anniversary of the largest mass execution in U.S. history. Thirty-eight Dakota men were hanged in Mankato, Minnesota, on December 26, 1862. The hangings came after the U.S./Dakota War in the summer of 1862. Lyle W. Miller's painting, "A Meeting of the Grandfathers," is featured in the Minnesota Historical Society's exhibit about the U.S./Dakota War of 1862. Miller is speaking on the war at the Prehistoric Indian Village in Mitchell on Friday at 2:00 pm.