If I had the ability to invent for the sake of the world I could Im not just clever. If I had to choose and international problem it'd be the war. I want to invent something that would cease this unstoppable mayhem od bloodshed. It's unnecessary and somebody invent something for this isue.
Maybe a cure for deadly diseases like Cancer and Aids.
Also, I would also like to discover the answer to interstellar travel so if in case we exhausted our planet's natural resources or if earth gets old then we a chance to go somewhere else and hopefully get settled on different places in the universe.