What is a good invention to write about and what 3 subtopics?

Try this list of famous inventions, and pick one you like:

http://inventors.about.com/od/astartinventions/a/FamousInvention.htm

Three topics you could cover might be:

1) How it was invented

2) Why it's useful

3) Disadvantages (like a cell phone going off at a movie or a wedding)