Nikola Tesla was one of the most influential inventor/scientist on modern day life. His genius is not nearly as well known as Alexander Graham Bell and Thomas Edison, however I think that his genius and knowledge far surpassed those two combined.
He viewed a world full of flying machines and electrical devices that were fueled by "broadcast power". Yes, power sent through the air and into whatever device needed it.
Wireless Power is now a reality. Researchers have devised the first devices to use a very limited broadcast method compared to Tesla's World Grid.
I can't wait to see what happens in the next 20 years.