In my opinion the most important invention was the airplane.This invention helped us to tranport long distances,from one country to another .When there are emergencies ,we can transport easily in short time.Also they have  created a rentable business at the airports.And  This invention have generated that others invents were created .For example:radars.What would happen if we did not have airplanes? ,I think we would lose contact with our  loved ones or many people would die for lack of  medicines in middle of a war or natural disasters.

On the other hand .What a shame that people use it to perverse interest like terrorist attack .I think inventions were created to do something good for humans not bad.