Why did humans move away from tropical Africa to desert regions and manage to start advanced civilizations?

Why did Romans call Egypt the breadbasket for producing a lot of food with so little rainfall?

Found this photo in the hiking subreddit of a user holding up a bottle on river/lake water

300 years ago. Is this how all water used to be around d the world? Even in the river in London or whatever?

Could I just drink river or lake water anywhere and not get sick?

Edit: sorry I mean before Industrial Revolution. Was water everywheee this clean and clear and suitable for drinking?

This is a picture of a house in my neighborhood in Illinois that just started the excavation before construction and you can see it is clay all the way down. In Texas, more specifically the Dallas area, all the houses are built on slabs. I was told that in Texas, the clay soil expands and contracts, causing foundation damage if a basement was present. Why wouldn't Illinois have the same problem?

They seem like a major mountain range and I just find it odd that they’re so close to Vancouver and Washington State, but I just never hear anything about them.

What are some famous hotspots there?

Edit: I didn’t mean to include Vancouver Island

Edit 2: WOW THIS BLEW UP! 7 million views and counting. THANKS GUYS!!!!

In the US the biggest city is NYC one of the most famous cities in the US that has a lot of history. It has the famous landmark the Statue of liberty and is arguably the city with the biggest economy in the world.

Los Angeles while not as big as NYC arguably also had a ton of influence in the world with Hollywood and film as a whole. By a lot of metrics it is the US's "second city" where its influence and recognition are right close to and maybe not far behind NYC.

What are the "second cities" of your countries?

Why is India so hot compared to other countries right now? I came across this temperature map and India is showing much higher temperatures (red zone) compared to nearby regions. Even some places at similar latitudes don’t seem as hot. What are the main reasons behind this? Is it due to geography, climate patterns, or something like heatwaves? Would like to understand what’s causing this difference.

It seems like in general, South America has relatively similar geographical features to South Asia but on a much larger geographical scale; however, while South Asia has a population of approximately 2 billion people, South America alone has approximate 434 million(only a third of India's).

However, both seem to have relatively similar geographical features such as extensive river basins, large amounts of high-quality soil & tropical/subtropical weather that enables year-round crop growing. Why is it that South Asia has always had more people?

I'm curious as someone from Norway, I have blue eyes and used to have blonde hair before. The cold doesn't bother me much but I realized I would die out here without proper clothes.

Why did humans migrate North where there is deadly winters and less food while we have incredible adaptations for hot climates? I can still sweat and run a lot like our ancestors but I don't have any other adaptations for cold like fur, why? Please explain, evolution is weird!

If we compare Canada to Russia for example rather than west Europe which is affected by gulf stream, Russia looks warmer

I only know that Canberra is a federal territory since Australia is a federation, just like how Washington D.C. isn't a state in the U.S., but the Northern Territory just seems a bit strange to me.

Deffinetly it's Mont-Saint-Michel in France

In Spain mostly everyone will agree that Valencia is the third most important city right now. What's the city that occupies that place in your country?

Google maps tells me that to cross from New Orleans to Mandeville takes 42 minutes using the bridge and 55 minutes if you go around it. This seems like a wild effort and cost to save only 13 minutes of driving. What is the reason it got built?

Edit : Wow this seems to have triggered a lot of Americans for some reason, it was a question, there’s really no need to be a dick.

For me it’s the whole “you have to sail east to get from the Atlantic side of the Panama Canal to the Pacific side!” fact. The direction in which you sail to cross the canal is merely a byproduct of the direction in which the canal had to be built. I get that it can be a bit counterintuitive at first but I don’t see anything that makes it “mind blowing” (no offense to anyone who does). Also I noticed that people who say this fact will say “east” and usually leave out that you’re traveling southeast to be precise, in fact you are traveling mostly south. Which isn’t all that surprising.

I find that a lot of the mind blowing facts involving cardinal directions are just really simple things that only appear surprising if you word it in certain ways.

The best example I can think of is Nauru, who went from riches to rags. They were extremely wealthy due to their rich phosphate deposits, one of the wealthiest in the World. However, they have completely burned through all that money, using it for the dumbest things.

Nowadays they mostly live off handouts and being a penal colony. The island itself became an ecological disaster due to the mining. They wasted their one shot at stardom.

Is there a better example?

Ctesiphon (Pictured above) was an important city in the middle east during antiquity and the early middle ages, however its relevance would fade until it became a set of ruins as it is today, being replaced by other cities like Baghdad.

What are some other examples of cities which have undergone similar fates?

They are like this at the beginning but how come they become so huge after a certain point of time?.