For most travelers, Nagasaki is a symbol of the horror and the inhumanity of war. An estimated 75,000 people perished in 1945 when the city became the second target of a nuclear attack. Today, Nagasaki’s Peace Park and Atomic Bomb Museum draw visitors from around the world. Often described as the San Francisco of Japan, the city occupies verdant hills surrounded by a deep-water bay. For three centuries, Nagasaki was Japan’s sole window on the world. The city is also celebrated as the setting for Puccini’s opera “Madame Butterfly.”