Was watching the episode "Thine Own Self" where Data got injured on Barkon IV and lost his memory, it occured to me that the advanced microscope he built was left behind. Now if I am not mistakened, that microscope would have been at least 200 years more advanced than anything they should have had.
Imagine if Da Vinci or Michaelangelo had access to a microscope that powerful in the Renaissance..how would that have changed our world? For good or bad?
Of course, Data also planted the concepts of the modern scientific method to Talur as well which could cause great changes as well if it spreads.