One thing that always strikes me when I look at maps of Alexander's empire is how his original capital in Macedon is almost at the extreme Western end of everything. His conquests took him very far East, but his Westernmost border never pushed that far beyond his starting point at all. This seems counter-intuitive, as you'd imagine the sphere of his control would naturally radiate outward in all directions from its center of gravity. I know he had designs on the West, but I'm wondering why he extended himself so far in one direction before even considering a Western campaign.