There are many intriguing cultural leftovers from our past civilizations. I will discuss some of them.
Alexander the Great discovered many ideas that we still use today. With the help of 35,000 Greeks and Macedonians Alexander managed to conquer and create his own empire from Greece to the borders of India. While on his journey he came up with the idea of getting on a horse from the left side. He found out that if you try to get on it from the right, your sword would be in the way. This idea is very practical, today we don't carry swords but we do still carry on the tradition of getting on a horse from the left.
One more idea that Alexander used in his days of battle was using the left side of the road for travel instead of the middle or right side. Alexander chose this technique because his army carried their swords on their right side.
If you were coming up on your enemy's army than you'd want to have easy access to your weapon. Today in Great Britain they still drive on the left side of the road, we think just because Alexander did.
Another idea that Alexander thought of that we still use today is the hair standards in the military. Alexander knew that if a young military man in an army had long hair his opponents would have something to grab onto when fighting. So, he devised a standard for his army. All young men in his army had to have shaved heads. This also contributes to today's military. Not only does the military force men and women to have short hair for fighting reasons but it is also in order to keep everyone looking somewhat the same for uniformity.
There are many more...