Today's word is "posterity". This is a noun which means future generations collectively.
For example, you can say, "We should take care of the environment for posterity's sake."
Want to master Microsoft Excel and take your work-from-home job prospects to the next level? Jump-start your career with our Premium A-to-Z Microsoft Excel Training Bundle from the new Gadget Hacks Shop and get lifetime access to more than 40 hours of Basic to Advanced instruction on functions, formula, tools, and more.