The Manhattan Project was an effort by the United States government to make the first atomic bomb. The most challenging part of the project was the difficulty in obtaining a large quantity of U-235 to use for fuel for the bomb. There were three bombs created: Gadget, Little Boy, and Fat Man. Gadget was a test bomb, Little Boy was detonated over Hiroshima, and Fat Man was detonated over Nagasaki. The bombs had safety features like lead shields to protect against radiation, fuses to guard against premature explosions, and neutron deflectors keep neutrons away from the larger mass.
Links to Information on the Manhattan Project
http://www.me.utexas.edu/~uer/manhattan/
http://library.thinkquest.org/17940/texts/timeline/manhattan.html?tqskip1=1
http://www.brook.edu/FP/PROJECTS/NUCWCOST/MANHATTN.HTM
http://www.eh.doe.gov/ohre/roadmap/achre/intro_3.html
http://www.spartacus.schoolnet.co.uk/USAmanhattan.htm
http://nuclearweaponarchive.org/Usa/Med/Med.html
http://nhs.needham.k12.ma.us/cur/mp/whos_who.html
http://www.yale.edu/lawweb/avalon/abomb/mpmenu.htm
http://wa.essortment.com/manhattanprojec_rgsu.htm
http://www.commondreams.org/views/080600-102.htm
