Turning points in history this week:Aug. 61806: Emperor Francis II abdicated, marking the end of the Holy Roman Empire after nearly a thousand years. 1945: During World War II, the U.S. B-29 Superfortress Enola Gay dropped an atomic bomb on Hiroshima, Japan, resulting in an estimated 140,000 deaths. 1942: U.S. and other allied forces landed at Guadalcanal, marking the start of the first major allied offensive in the Pacific during World War II. Aug. 81814: During the War of 1812, peace talks between the United States and Britain began in Ghent, Belgium. 1854: Henry David Thoreau’s “Walden,” which described Thoreau’s experiences while living near Walden Pond in Massachusetts, was first published.