Egyptian pyramids are not where they're supposed to be. Why?
Why is Cairo, the biggest African city, where it is today?
Alexandria?
Why do over 100M Egyptians live so densely clustered?
These questions all have the same answer. Look:
1st map: population density
2nd map: satellite
The "flower" is the inhabited part of Egypt, which is basically the Nile
It makes sense: outside of the Nile, Egypt is like the rest of the Sahara desert, an inhospitable hell for humans
That's because it's in the Horse Latitudes, which receive winds from the high atmosphere that fall here devoid of any moisture
The Nile is the one river that crosses these Horse Latitudes, and hence the Sahara
The Nile brings so much water and sediment with it that its entire banks are incredibly fertile. Its annual floods expanded the river, making kms around it fertile.
Fertility➡️agriculture➡️food➡️people
And why such massive floods?
The Nile starts in the Ethiopian highlands, which don't get big snowpacks (too close to the equator, not high enough)
Monsoons don't become ice. They just flood down.
So that's why Egypt was built around the Nile
It made sense to build the pyramids near it too: 1. This is where people lived 2. How else could you carry stones that weigh 3 to 15 tons if not by boat?
Here's the problem though: Many Egyptian pyramids are NOT so near the Nile!
In the delta to the north it makes sense: River arms are cosntantly changing there. But what about these south of Cairo?
These are several km away from the Nile! Why so far? How could Egyptians carry stones all the way there?
One tip comes from a topographic map (left) vs the map of the Giza pyramids (right). Notice how they're on a ridge, while the fertile floodplain is at their feet?
It turns out an arm of the Nile reached that area in the past! We know because scientists found ancient pollen in the area consistent with this type of environment
Could another arm of the Nile have reached the other pyramids? Maybe from the Faiyum area, a huge green area watered by the Nile?
Impossible: the ridge on which the Giza pyramids stand is big!
Left: topographic map
Right: exaggerated relief map
Where are these pyramids exactly? If we trace a path between them, we see... a parallel path to the Nile today, east of that ridge!
Was there an arm of the Nile there in the past?
It appears so! A team of scientists shared at the end of 2023 the discovery of the "Ahramat Branch". They found it thanks to the latest radar technology
Egyptians would have enjoyed building pyramids on the banks of the calmer branch
So the pyramids followed rivers after all
And why is Cairo where it is?
Here's a satellite picture of the delta of the Nile. Guess where Cairo is?
At the head of the delta!
It makes sense:
• The arms move all the time, but the head doesn't
• If you want to control both the upper Nile and the Delta, you better control that point
• It's the natural point of trade between the delta and the upper Nile
And you can see why the delta starts where it does: It's the topography! It's where the ridges left and right end. The Nile has been releasing sediments for millions of years into the delta, growing it little by little every year
And topography doesn't change. That's why the Giza pyramids and Cairo are at the same place today
This is also why Alexandria, the 2nd most important Egyptian city, is where it is, the westernmost part of the delta:
• It still gets freshwater from the Nile
• It's the only viable port in the delta, because east of it there's too much Nile sediment
And so this is why the topography of Africa has created the Nile, Egypt, its 110M Egyptians, and placed Cairo, Alexandria, and its pyramids where they are
Here's a short video on Egypt (narrated)
But why has that made Egypt an authoritarian regime today?
Why is it a US ally?
Why are Egypt's borders where they are?
Why is Egypt so old, yet only recently an independent country?
I answer these questions here:
I respect @BillAckman a lot but I think he's wrong on @Uber. AFAIK his bear case on robotaxis: 1. Not great for bad weather 2. Too expensive to cover peak demand 3. Less utilization because of food delivery 4. They can't disintermediate Uber
1. Not great for bad weather
This is a @Waymo driving in rain—the worst they'll ever be! They already have ~10x fewer accidents than humans. Maybe in the short term humans are going to be better in some really bad weather, but those are short-term exceptions
2. Robotaxis will be too expensive to cover peak demand
This is ptrobably true for Waymo but not @Tesla's @robotaxi, for 2 reasons:
a. Cybercab costs will be the same order of magnitude as normal ICE cars
The Model 3 costs ~$40-$45k, but the Cybercab will have 60% fewer parts: steering wheel, pedals, steering column, backseats, backdoors, side-window mirrors, rear window... Let's assume this will bring the cost down to $30-$35k
Add to that the new manufacturing process that treats Tesla's Cybercabs not as cars, but as electronics. They will be able to produce a car every 5s. This will further reduce their price
Compare that to the price of a car for Uber, which today is between $25k-$60k
Never bet against the US:
Ppl think its biggest strength is its institutions, the dollar, entrepreneurship... But one of its biggest assets is its geography 🧵
1. Size
The US is the 4th largest country. It spans an entire continent, reaches two oceans, and is big enough to be a geographic heavyweight in the world
2. The Mississippi Basin
It's the 4th largest drainage basin in the world and occupies 40% of the contiguous 48 US states, touching 32 of the US’s 50 states. 11 US states directly take their name from it.
Climate caused the US Civil War, because: 1. Slavery was the main cause of the war 2. Different crops were the main cause of slavery 3. Climate caused different crops in the North vs South
This is terribly important to understand the US today and how to heal it
🧵
1. Slavery was the main cause of the war: the Abolitionist North & the Slavery South were competing to expand westward to increase their political influence
But the North grew & expanded faster, to a point where it could force abolition on the South, which then seceded
In 1790, the Free & Slave states had the same population, and there were many more Slave States (8 vs 5), so Slave States controlled the Senate.
By the eve of the war in 1860, the North had 50% more population and 4 more states, giving them control of both the House & Senate
Moscow is one of the weirdest capitals:
• Biggest European city
• Extremely cold
• Little farmland
• To Russia's extreme west
• Not on a coast or main river
How did it create the biggest country on Earth?
It involves horse archers, human harvesting & tiny animals 🧵
The first shocking fact is that Russia is so far north it's at the edge of arable land. How can you create a capital with so little food? Why not in the middle of the most fertile area on Earth?
This far north is extremely cold
Moscow is the 3rd coldest capital in the world and by far the biggest: with 20M ppl, its metro population is 8x bigger than the 2nd biggest cold capital, Stockholm!
This map tells you how a seemingly innocent difference, like wheat vs rice eating, can have dramatic political, economic, and cultural ramifications:
🧵
The areas that harvest wheat vs rice are different. Why?
Because of climate
Rice needs heat and lots of water. Ideally, flooding the fields to also kill weeds. Rice dies with frost.
Wheat resists it well, prefers cooler temperatures, but dies when it's flooded
Did you know the West's trade deficits to China are not recent, but started 2000 years ago? This is the story of how silk, porcelain, tea, opium, and silver have determined the history of the world 🧵
The Romans already complained about deficits to China! Mainly because of silk
Back then the Chinese already preferred manufacturing and selling products than consuming foreign products. Chronicler Solinus ~200 AD: The Chinese "prefer only to sell their products, but do not like to buy our goods."