The blast at Trinity was felt and seen for hundreds of miles, so naturally, people noticed.
Anticipating curiosity over such a huge explosion, Groves released a statement that what everyone saw was the explosives dump at Alamogordo Air Base blowing up.
Meanwhile, Major Robert Furman and Captain James Nolan are escorting the gun assembly and the uranium, under strict supervision at all times, on its way to Tinian via the Indianapolis.
At Potsdam, Truman is elated with the news from Groves that the bomb worked. The stats are unbelievable, and he can't wait to shock Stalin.
He tells Stalin that they've discovered a new highly destructive weapon, and Stalin basically shrugs and says, "Good. Use it on Japan."
Truman and Churchill are perplexed by his lack of reaction, not knowing that he knows all about their bomb project.
Japan is refusing to surrender despite horrific losses. Truman is convinced that continuing the status quo will result in an untold number of American casualties, so it's time to drop the bomb and hopefully shock the Japanese into surrender.
July 26, Truman and Churchill issue the Potsdam Declaration, which demands the Japanese unconditionally surrender or face total destruction.
Japan is torn. The Big Six—their top political and military leaders—are at odds because the politicians want to accept the terms but the military dudes are like, "Uh, no way. Unconditional surrender is way too much of a disgrace."
The Prime Minister of Japan, Baron Suzuki, breaks the tie and gives a big thumbs down to the Potsdam terms.
Colonel Tibbets is given the orders to drop the bomb as soon as weather permits.
Robert Serber and a team of physicists fly out to Tinian to assemble the uranium bomb, which they nickname Little Boy.
Finally, on August 5 the cloudy conditions over Japan dissipate, and they all agree they can deliver the bomb the next day.
Little Boy is loaded onto the Enola Gay.
Tibbets is more than a little concerned about take off, due to the short runway and his very heavy load, but despite a few very tense moments, the Enola Gay safely makes it into the air.
Tibbets and his crew fly toward Japan and get the coded message that their target (determined by weather and how clear the mission would be) is Hiroshima.