The B-29, of which we see depicted in the illustration the model 45 MO named as "Enola Gay", the very one which dropped over Hiroshima the first atomic bomb ever dropped in History, can be fairly regarded as the maximum expression of the American war industry and almost a science-fiction machine for its time. The aircraft was almost entirely designed and built by using vanguard techniques and by using the traditional formulas to a minimum extent. The Boeing B-29 (which flew for the first time the 21st September 1942) was a four-engine aircraft of very elegant line and entirely metallic construction, with the exception of the movable surfaces, with the wings placed in middle position, and fitted with a fully retractable landing gear of tricycle type with fore wheel, and an auxiliary tail ski to avoid making contact with the ground when taking off or landing. The fuselage, one of cylindrical shape, housed the crew in two compartments (one in the nose and another one in the middle section, which were linked by a tube of about 90 centimeters in diameter, along which the crew members transited by lying in a carriage and taking impulse by means of a rail which was attached to the upper part of the tube). During flight the two compartments were pressurized, and they had installations for heating and oxygen breathing. Only the tail machine gunner was isolated from the rest of the crew, in his individual position, during high-altitude flights. The propulsion system comprised four Wright R 3350 13 engines, which would soon be replaced by more adequate propulsors, for they provided only 2230 horsepower each, which was not much for an aircraft having the mass of the B-29. The electronic equipment comprised radar devices for fire control, and later for bombing. The offensive load was housed in two bays, which were fitted with devices which prevented that the bombs fell in groups, and regularly spaced their fall. The defensive system comprised from ten to twelve 12.7-millimeter machine guns plus one 20-millimeter cannon, and every weapon, with the exception of the tail weapon, was installed in turrets which were remotely controlled by the gunners, who saw the enemy through windows which were placed away from the weapons. In this way a better shooting precision was achieved, because the gunners were not subject to the handling of the weapons when firing them. It is interesting to mention that an identical solution had been previously developed only by Italian designers in the Piaggio 108, the excellent four-engine bomber aircraft which was produced in Italy at the end of 1939. But in some cases the aircraft were either armed only with the tail machine gun or totally unarmed, as the "Enola Gay" was. The B-29 was as well the biggest help which the United States provided, albeit unintentionally, to the Soviet Union. This is how it happened. Between July and November 1944, three B-29 had to effectuate a forced landing in Siberia, for they could not reach their bases located in Chinese territory. Trusting the bonds of the alliance between both countries, the crews expected to be able to repair the malfunctions and depart again, but they found themselves in front of the unfriendly muzzles of the machine guns of the Russian fighter aircraft, which forced them to land and to follow the also unfriendly muzzles of the submachine guns of the Red Army soldiers, who proceeded to intern them. The aircraft were seized and put at the disposal of the technicians led by engineers Tupolev and Schvetsov, who after a hard work, which would mean an exceptional effort for the Soviet war industry, would manage to present the first "Russian" strategic superbomber aircraft to Stalin in August 1947. In this way the Tupolev 4 had been born and the American absolute aerial supremacy had died. The "hot war" had ended and the "cold war" had started.