Hello! Thanks for your question!
The Manhattan Project was a United States government project. It was a research project during WW II where they figured out how to create and created the world’s first atomic bombs.
First Atom Bomb:
Here are some websites with more information:
http://www.britannica.com/EBchecked/topic/362098/Manhattan-Project
http://science.howstuffworks.com/manhattan-project.htm
http://library.thinkquest.org/17940/texts/timeline/manhattan.html
If you need anymore information, please let me know.
Take care!
Mrs. M.