Question: Where did the bomber flown by Frederick Bock famously drop an atomic bomb on?
Context: The W21 was an hydrogen bomb design for the US military.  It would have used the physics package of the TX-21 bomb.  The TX-21 was a weaponized version of the "Shrimp" device tested in the Bravo shot of Operation Castle.  A TX-21C was tested as the Navajo shot, Operation Redwing.  The TX-21, was a scaled-down version of the Runt device (M-17 hydrogen bomb).  Smaller in size and weight to the Mk-17, the Mk-21 was considered as a potential missile warhead.  Far more powerful than the TX-13, which was a high-yield atomic bomb developed from the Mk-6 bomb, the XW21 was to replace the XW13 in the weapons pod of the B-58 bomber and for the SM-64 Navaho missile. The Heinkel He 177 "Greif" ("griffin") was a large long-range heavy bomber flown by the Luftwaffe during World War II.  In general terms, the He 177 had payload/range capability similar to strategic bombers in the USAAF and RAF, although it had much higher figures for its cruising and maximum speeds. Joan Elizabeth Curran (26 February 1916 – 10 February 1999) was a Welsh scientist who played important roles in the development of radar and the atomic bomb during the Second World War.  She invented chaff, a radar countermeasure technique credited with reducing losses among Allied bomber crews.  She also worked on the development of the proximity fuse and the electromagnetic isotope separation process for the atomic bomb. Two Bombs, One Satellite (Chinese:两弹一星) was an early nuclear and space project of the People's Republic of China.  "Two Bombs" refers to the Atomic bomb (and later the Hydrogen bomb) and Intercontinental Missile, while "One Satellite" refers to artificial satellites.  China tested its first atomic bomb and hydrogen bomb in 1964 and 1967 respectively, while in 1970 the country successfully launched its first satellite (DFH-1).  23 scientists involved in the project was awarded the title "Two bombs and one Satellite Award" (Chinese:两弹一星功勋奖章) in 1999. The Bristol Bombay was a British troop transport aircraft adaptable for use as a medium bomber flown by the Royal Air Force (RAF) during the Second World War. Major General Charles W. Sweeney (December 27, 1919 – July 16, 2004) was an officer in the U.S. 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. The Boeing B-29 Superfortress is a four-engine propeller-driven heavy bomber designed by Boeing, which was flown primarily by the United States during World War II and the Korean War.  It was one of the largest aircraft operational during World War II and featured state of the art technology.  Including design and production, it was the single most expensive weapons project undertaken by the United States in World War II, exceeding the cost of the Manhattan Project by between $1 and 1.7 billion.  Innovations introduced included a pressurized cabin, dual-wheeled, tricycle landing gear, and an analog computer-controlled fire-control system that directed four remote machine gun turrets that could be operated by a single gunner and a fire-control officer.  A manned tail gun installation was semi-remote.  The name "Superfortress" continued the pattern Boeing started with its well-known predecessor, the B-17 Flying Fortress.  Designed for the high-altitude strategic bomber role, the B-29 also excelled in low-altitude nighttime incendiary bombing missions.  One of the B-29's final roles during World War II was carrying out the atomic bomb attacks on Hiroshima and Nagasaki. The Enola Gay ( ) 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. Frederick C. Bock (January 18, 1918 – August 25, 2000) was a World War II pilot who took part in the atomic bombing of Nagasaki in 1945, flying the B-29 bomber "The Great Artiste", which was used for scientific measurements of the effects caused by the nuclear weapon.  The bomber which actually dropped Fat Man was called "Bockscar" as it was usually flown by Frederick Bock.  The staff was swapped just before the raid and Major Charles Sweeney piloted "Bockscar", which flew with "The Great Artiste" and another aircraft.  A native of Greenville, Michigan, Bock died at his Arizona home in 2000, of cancer. Big Stink – later renamed Dave's Dream – was a United States Army Air Forces Boeing B-29-40-MO Superfortress bomber (Victor number 90) that participated in the atomic bomb attack on Nagasaki, Japan on August 9, 1945.  Assigned to the 393d Bomb Squadron, 509th Composite Group, it was used as a camera plane in support of the bomb-carrying B-29 "Bockscar" to photograph the explosion and effects of the bomb, and also to carry scientific observers.  The mission was flown by crew C-14 but with Group Operations Officer Major James I. Hopkins, Jr., as the aircraft commander.
Answer: Nagasaki