'Lord, these affairs are hard on the heart': How Manhattan Project scientists reacted to the world's first atomic bomb test

We see an enormous yellow bubble that is an atomic bomb exploding against a black sky.

On July 16, 1945, an enormous column of smoke rose up to 30,000 feet (9,144 meters) high above a remote part of the Jornada Del Muerto Desert, New Mexico, preceded by a tremendous flash that lit up the entire sky.

Watched by the military and a group of scientists some 20 miles (32 kilometers) away, this was a crucial moment in World War II, and marked a turning point in world history — the successful first test of the atomic bomb.