Maybe if I had a few less beers in me I'd be able to come up with something specific (not like I should though).

I'd go for something that enhanced the area of exploration and/or transportation that came about due to a particular need of a government, state, culture or society. You could also go the route of weapons since in the 17th century naval warfare was the only game in town besides running at each other on a battlefield with muskets and stuff.

Air travel, submarines, space travel, nuclear weapons...