Who was the second nation to develop an atomic bomb?

What were the causes of labor unrest at the end of world war 1? What is similar about the Monitor and the Merrimack? Did either side in the civil war have the bigger advantage at the start of the war? Why was a German assault on Stalingrad a crushing defeat for the Germans? What famous people used to live or still live in Florida? What was the Indian prototype of decolonization movements? What did boys wear 100 years ago? Did Joseph Hooker the Civil War general have children? I have the game command and conquer the first decade but can't find the case with the codes on it. Do you know them? What weapons came out during World War 1? What is the plural of of enemy? Why did people invented nuclear weapons? Who as the first person to get killed during World War 2? What is the imperial army? What state is the pentagon in? Who vowed that he would return to the Philippines? What Black powder rifles used in world war 1? Describe how general Grant conducted the Confederate surrender? How did women contribute to Americans war effort in world war1? What is the paper currency printed by the union government that fell victim to wartime inflation?