paragraph_text: During the early years of the Cold War from 1946 to 1958, the United States tested 67 nuclear weapons at its Pacific Proving Grounds located in the Marshall Islands, including the largest atmospheric nuclear test ever conducted by the U.S., code named Castle Bravo. "The bombs had a total yield of 108,496 kilotons, over 7,200 times more powerful than the atomic weapons used during World War II." With the 1952 test of the first U.S. hydrogen bomb, code named "Ivy Mike," the island of Elugelab in the Enewetak atoll was destroyed. In 1956, the United States Atomic Energy Commission regarded the Marshall Islands as "by far the most contaminated place in the world."

paragraph_text: At Princeton, the physicist Robert R. Wilson encouraged Feynman to participate in the Manhattan Project—the wartime U.S. Army project at Los Alamos developing the atomic bomb. Feynman said he was persuaded to join this effort to build it before Nazi Germany developed their own bomb. He was assigned to Hans Bethe's theoretical division and impressed Bethe enough to be made a group leader. He and Bethe developed the Bethe–Feynman formula for calculating the yield of a fission bomb, which built upon previous work by Robert Serber.

paragraph_text: Paul Warfield Tibbets Jr. (23 February 1915 -- 1 November 2007) was a brigadier general in the United States Air Force. He is best known as the pilot who flew the Enola Gay (named after his mother) when it dropped Little Boy, the first of two atomic bombs used in warfare, on the Japanese city of Hiroshima.

paragraph_text: 6998150000000000000 ♠ 1.5 × 10 -- 6998200000000000000 ♠ 2 × 10 17.4 -- 23.2 GWh The Little Boy atomic bomb dropped on Hiroshima on August 6, 1945, exploded with an energy of about 15 kilotons of TNT (63 TJ), and the Fat Man atomic bomb dropped on Nagasaki on August 9, 1945, exploded with an energy of about 20 kilotons of TNT (84 TJ). The modern nuclear weapons in the United States arsenal range in yield from 0.3 kt (1.3 TJ) to 1.2 Mt (5.0 PJ) equivalent, for the B83 strategic bomb.

paragraph_text: During the final stage of World War II, the United States dropped nuclear weapons on the Japanese cities of Hiroshima and Nagasaki on August 6 and 9, 1945, respectively. The United States had dropped the bombs with the consent of the United Kingdom as outlined in the Quebec Agreement. The two bombings, which killed at least 129,000 people, remain the only use of nuclear weapons for warfare in history.

paragraph_text: ``Little Boy ''was the codename for the atomic bomb dropped on the Japanese city of Hiroshima on 6 August 1945 during World War II by the Boeing B - 29 Superfortress Enola Gay, piloted by Colonel Paul W. Tibbets, Jr., commander of the 509th Composite Group of the United States Army Air Forces. It was the first atomic bomb to be used in warfare. The Hiroshima bombing was the second artificial nuclear explosion in history, after the Trinity test, and the first uranium - based detonation. It exploded with an energy of approximately 15 kilotons of TNT (63 TJ). The bomb caused significant destruction to the city of Hiroshima and its occupants.

paragraph_text: In 1958 as part of an experiment, Operation Argus, the United States Navy detonated an atomic bomb 160 kilometres (100 mi) high in the upper atmosphere about 175 kilometres (109 mi) southeast of the main island.

paragraph_text: In November 1945, Eisenhower returned to Washington to replace Marshall as Chief of Staff of the Army. His main role was rapid demobilization of millions of soldiers, a slow job that was delayed by lack of shipping. Eisenhower was convinced in 1946 that the Soviet Union did not want war and that friendly relations could be maintained; he strongly supported the new United Nations and favored its involvement in the control of atomic bombs. However, in formulating policies regarding the atomic bomb and relations with the Soviets, Truman was guided by the U.S. State Department and ignored Eisenhower and the Pentagon. Indeed, Eisenhower had opposed the use of the atomic bomb against the Japanese, writing, "First, the Japanese were ready to surrender and it wasn't necessary to hit them with that awful thing. Second, I hated to see our country be the first to use such a weapon." Initially, Eisenhower was characterized by hopes for cooperation with the Soviets. He even visited Warsaw in 1945. Invited by Bolesław Bierut and decorated with the highest military decoration, he was shocked by the scale of destruction in the city. However, by mid-1947, as East–West tensions over economic recovery in Germany and the Greek Civil War escalated, Eisenhower gave up and agreed with a containment policy to stop Soviet expansion.

paragraph_text: In 1945, the sinking of Indianapolis led to the greatest single loss of life at sea, from a single ship, in the history of the US Navy. The ship had just finished a high - speed trip to United States Air Force Base at Tinian, to deliver parts of the first atomic bomb ever used in combat (the United States' Little Boy atomic bomb), and was on training duty. At 0015 on 30 July 1945 the ship was torpedoed by the Imperial Japanese Navy submarine I - 58. The ship, on her way to the Philippines, sank in 12 minutes. Of 1,196 crewmen aboard, approximately 300 went down with the ship. The remaining 900 faced exposure, dehydration, saltwater poisoning, and shark attacks while floating with few lifeboats and almost no food or water. The Navy learned of the sinking when survivors were spotted four days later by the crew of a PV - 1 Ventura on routine patrol. Only 317 survived.

paragraph_text: During the final stage of World War II, the United States dropped nuclear weapons on the Japanese cities of Hiroshima and Nagasaki on August 6 and 9, 1945, respectively. The United States had dropped the bombs with the consent of the United Kingdom as outlined in the Quebec Agreement. The two bombings killed at least 129,000 people (most of whom were civilians) and remain the only use of nuclear weapons in the history of warfare.

paragraph_text: The Enola Gay (/ ɪˈnoʊlə ˈɡeɪ /) is a Boeing B - 29 Superfortress bomber, named for Enola Gay Tibbets, the mother of the pilot, Colonel Paul Tibbets, who selected the aircraft while it was still on the assembly line. On 6 August 1945, during the final stages of World War II, it became the first aircraft to drop an atomic bomb. The bomb, code - named ``Little Boy '', was targeted at the city of Hiroshima, Japan, and caused unprecedented destruction. Enola Gay participated in the second atomic attack as the weather reconnaissance aircraft for the primary target of Kokura. Clouds and drifting smoke resulted in a secondary target, Nagasaki, being bombed instead.

paragraph_text: Peter Adolf Thiessen (6 April 1899 – 5 March 1990) was a German physical chemist. He voluntarily went to the Soviet Union at the close of World War II, and he received high Soviet decorations and the Stalin Prize for contributions to the Soviet atomic bomb project.

paragraph_text: Charles W. Sweeney (December 27, 1919 -- July 16, 2004) was an officer in the United States Army Air Forces during World War II and the pilot who flew Bockscar carrying the Fat Man atomic bomb to the Japanese city of Nagasaki on August 9, 1945. Separating from active duty at the end of World War II, he later became an officer in the Massachusetts Air National Guard as the Army Air Forces transitioned to an independent U.S. Air Force, eventually rising to the rank of major general.

paragraph_text: Behind the scenes, the Soviet government was working on building its own atomic weapons. During the war, Soviet efforts had been limited by a lack of uranium but new supplies in Eastern Europe were found and provided a steady supply while the Soviets developed a domestic source. While American experts had predicted that the Soviet Union would not have nuclear weapons until the mid-1950s, the first Soviet bomb was detonated on August 29, 1949, shocking the entire world. The bomb, named ``First Lightning ''by the West, was more or less a copy of`` Fat Man'', one of the bombs the United States had dropped on Japan in 1945.

paragraph_text: On 6 August 1945, the U.S. dropped an atomic bomb on the Japanese city of Hiroshima in the first nuclear attack in history. In a press release issued after the atomic bombing of Hiroshima, Truman warned Japan to surrender or "...expect a rain of ruin from the air, the like of which has never been seen on this earth." Three days later, on 9 August, the U.S. dropped another atomic bomb on Nagasaki, the last nuclear attack in history. More than 140,000–240,000 people died as a direct result of these two bombings. The necessity of the atomic bombings has long been debated, with detractors claiming that a naval blockade and aerial bombing campaign had already made invasion, hence the atomic bomb, unnecessary. However, other scholars have argued that the bombings shocked the Japanese government into surrender, with Emperor finally indicating his wish to stop the war. Another argument in favor of the atomic bombs is that they helped avoid Operation Downfall, or a prolonged blockade and bombing campaign, any of which would have exacted much higher casualties among Japanese civilians. Historian Richard B. Frank wrote that a Soviet invasion of Japan was never likely because they had insufficient naval capability to mount an amphibious invasion of Hokkaidō.

paragraph_text: The war in Europe concluded with an invasion of Germany by the Western Allies and the Soviet Union, culminating in the capture of Berlin by Soviet troops, the suicide of Adolf Hitler and the subsequent German unconditional surrender on 8 May 1945. Following the Potsdam Declaration by the Allies on 26 July 1945 and the refusal of Japan to surrender under its terms, the United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki on 6 and 9 August respectively. With an invasion of the Japanese archipelago imminent, the possibility of additional atomic bombings and the Soviet invasion of Manchuria, Japan formally surrendered on 2 September 1945. Thus ended the war in Asia, cementing the total victory of the Allies.

paragraph_text: In the United States, where Fermi and Szilárd had both emigrated, this led to the creation of the first man - made reactor, known as Chicago Pile - 1, which achieved criticality on December 2, 1942. This work became part of the Manhattan Project, a massive secret US government military project to make enriched uranium by building large reactors to breed plutonium for use in the first nuclear weapons. The US tested atom bombs and eventually these weapons were used to attack the cities of Hiroshima and Nagasaki.

paragraph_text: Every August 6, "A-Bomb Day", the city of Hiroshima holds the Peace Memorial Ceremony to console the victims of the atomic bombs and to pray for the realization of lasting world peace. The ceremony is held in front of the Memorial Cenotaph in the Hiroshima Peace Memorial Park. Participants include the families of the deceased and people from all over the world. This traditional ceremony began in 1947 by the then Hiroshima Mayor Shinzo Hamai.

paragraph_text: The Making of the Atomic Bomb is a contemporary history book written by the American journalist and historian Richard Rhodes, first published by Simon & Schuster in 1987. It won the Pulitzer Prize for General Non-Fiction, the National Book Award for Nonfiction, and a National Book Critics Circle Award. The narrative covers people and events from early 20th century discoveries leading to the science of nuclear fission, through the Manhattan Project and the atomic bombings of Hiroshima and Nagasaki.

paragraph_text: Leona Harriet Woods (August 9, 1919 – November 10, 1986), later known as Leona Woods Marshall and Leona Woods Marshall Libby, was an American physicist who helped build the first nuclear reactor and the first atomic bomb.

Question: Who dropped the atomic bomb on the city where the first atomic bomb used in war exploded?
Answer: Paul Warfield Tibbets Jr.