Two thousand years ago the Roman 11 stretched from Britain to Egypt. Its armies did not win by force alone. Engineers built straight roads so that 12 could move quickly from one border to another, and Roman law gave conquered towns a reason to stay quiet. Later 13 still argue about the moment when the system began to fail. Most of them agree that no single 14 destroyed it. Money lost its value, the borders grew far too long, and generals fought one another instead of the enemy. In the end the empire did not 15; it simply came apart.
In 1805 a British fleet met a much larger French and Spanish force off the coast of Spain. The battle changed 16 warfare for a century. Instead of forming one long line, the British admiral cut the enemy line in two, a 17 move that nobody had expected. Thick smoke soon filled the air and 18 was complete; captains could not even see their own ships. By evening the British had 19 eighteen enemy vessels and lost none of their own. The admiral himself died on deck, but his 20 victory is still studied in every naval college today.