I know that the Roman Empire had land trade along the Nile River, which provided water. But how about west of the Nile Valley? Did the Romans have any means of crossing the rather dangerous Sahara?

A lot of this will depend on whether the dromedary camel was domesticated in the western region back then. The Romans had donkeys, but donkeys cannot go without a drink for a long period as a dromedary camel can.

The dromedary was definitely used by the later Arabs and Berbers in more recent times in the Sahara, but was it around, say south of Libya 2000 years ago?

I've seen articles saying that millions of pills of what was (essentially) crystal meth were given to front line soldiers. How true is this and is their any analysis on the effect that it had on the German war effort?

When constructing aquaducts from the source on the highest point a distance away from the desired distribution point for the water, and at a precise gradient to ensure consistant flow, Roman engineers seemingly understood the effects of gravity but how did they explain the phenomenon? Did they assume that gravity was a property of water or of anything that "rolled downhill"?

Im writing an essay based on this question, and would REALLY appreciate it if someone of knowledge would share with me some research papers, journals, anything. Thanks a lot!

This may be an overstatement, but in a sense the United States is the cultural world power. Why is this? Many people in foreign countries know American songs, American food, American movie stars, American movies, and so on. How did this come to be?

I heard a story about a general that got hit by arrow right in the eye and he just pulled it out like a kebab and ate it in front of everyone. Any truth to this?

Ok, so I have recently taken up a real interest in the World Wars, specifically dealing with the Science side of it, but I don't know what sources would be really credible to use. I want to make sure I can get the full picture of both wars so I can fully understand the Science aspects of them too. I would also like to learn more about the Cold War and what both the Americans/Soviets created during this time. Anything given is appreciated.

Specifically with respect to European monarchs.

I understand that this is a very general question, but I'm looking forward to any example given. I was told by a colleague that 'the vast majority of humans that have ever lived would live and die within 100 km of their place of birth', and I was wondering if this statement would hold true (even if it held true at all) for nomadic peoples.

Was it because the older Romans clinged to tradition or so that they had atleast some sort of spear unit against cavalry?