I believe the railroad and the invention of the telephone were the most important. The railroad allowed Americans to travel from coast to coast in very little time. The telephone allowed for instant communication as before a letter would take weeks to receive.
Egypt has always been a target for colonial control due to the Nile and the many trade routes flowing through and around it. The Nile allowed for easier access to the interior of Africa and the nations and resources that could be found within. The trade routes that flowed into and around Egypt also brought in great wealth and riches. By controlling these, a nation could gain access to resources that they could charge a premium for to others.
