Safe investments in theory don't exist. The safes would be a savings account or bank cd. When I would like to say they are safe they aren't at all. The bank can go under at anytime, or the government could collapse at any time.
With that being said, I would say a really safe investment would be a metal like gold or silver. While I say that now I cannot be sure, its highest then it has ever been ever, so it might crash.
I would lastly say invest in your education or in your passion, but then again both are temporary. Anyone at anytime can lose their minds to Alzheimers or pass away, and your passions can change at any time in your life.
There are no safe investments, its a term designed around risk.