Nuclear weapons (Hitler is an American---Version 1)

Belligerents of the Second World War have learned about the possibilities of creating a weapon from a massive release of energy from mass. During the war, that race accelerated, with the Americans, Iranians and Germans seemingly in the lead (there was no telemark bombing ATL). In February 1943, the first Atomic tests occurred in Nevada. Iran followed in days. They both gave the Axis an ultimatum of surrender, but the Axis refused, even though Britain had lost much of Canada(except for some of southern Quebec) and the Mexican strategy failed. So an American Bomber on Iceland(which joined the Allies in 1942) flew over London and deployed a single Uranium bomb that annihilated the city from St Paul cathedral onwards, and left the River Thames a radioactive sludge for decades, effectively knocking out the British Empire. Iran followed suit days later when a VTOL A-16 bomber (with 4 rotors rather than 2 due to the bomb's weight) and a fighter escort flew over Rome and deployed a Plutonium Bomb obliterating Rome and killing Mussolini. Germany's response was flying an experimental V-3 rocket (which had the range of an IRBM) from Quebec to Washington DC. Fortunately for the USA, the federal government had relocated to Denver, Colorado. For that attack, a US plane form Britain flew for Berlin and deployed a single Nuclear bomb that reduced the city to dust. Meanwhile, a British bomber carrying its own atomic bomb was bound for Tehran but was shot down by F-3 fighters over Iraq.