The introduction of cannon into warfare meant that walled cities and towns were of no great use, and opened the way to open cities and towns with suburbs.
Around 1500, Leonardo da Vinci was designing and possibly making a variety of mechanical devices and siege engines to carry out a variety of warlike functions.
Most of the work done on developing rockets was done on military budgets, mainly by people like Robert Goddard and von Braun, who just wanted to get into space.
This file is http://members.ozemail.com.au/~macinnis/scifun/splats.htm, first created on February 16, 2008. Last recorded revision (well I get lazy and forget sometimes!) was on February 16, 2008.