There's a lot to be said in the book.

It begins with the prosperity of society before the cataclysm, but many things are exaggerated.

Of course, it is not an exaggeration, and if this era of cataclysm is the situation after the development of Chang Fa's era twenty or thirty years later, Chang Fa feels that many things are still possible.

It's like a street train floating in the air.

The book says that this is a magnetic levitation technology, but Chang Fa feels that its description is a little unobjective, because this train is not simply suspended a few centimeters or more than ten centimeters high on the surface, but directly above five meters on the surface.

The book says that after the emergence of this technology, the probability of a car accident has been avoided to a large extent, as if it means that when the car flies above five meters, it forms two layers with the pedestrians on the ground, so the car and the pedestrian will not collide again.

Looking further down, Chang Fa saw the scene that occurred in the cataclysmic era.

The author said that many things were obtained by him through research, which is not necessarily entirely correct, but it is very probable.

The cause of the cataclysm is described differently in different places, but it is agreed that there was a war between two huge forces over the position of world supremacy.

Then one of the factions went berserk in civil strife and launched a nuclear bomb against the other, and then a major war broke out between the two sides.

This crazy nuclear war triggered the madness of all the countries of the earth, and as a result, a large-scale nuclear war broke out, and the entire earth was instantly turned into ruins.

At that time, people always said that when all the nuclear bombs on the earth broke out, the entire earth could be destroyed, but after the nuclear war really broke out, the earth did not show any signs of destruction, but human civilization was almost destroyed.

In the war, all nuclear bombs were dropped in the direction of the central city, and tens of thousands of nuclear bombs bombed them, and all cities, almost every city, in every country, were destroyed, and only those in the remote areas survived.

There were also people who hid in bomb shelters in advance and survived.

But the biggest threat after the nuclear war is radiation, almost the entire earth is covered by radiation, and many people have almost lost their lives even when they come out of the bomb shelter, or even if they are not threatened by the explosion of a nuclear bomb.

For the first 100 years of the cataclysm, humanity was in an endangered state and could be wiped out at any time, but eventually it slowly recovered.

In the two hundred years since the cataclysm, people have slowly gathered their forces, by which time the radiation has dissipated a lot, and the threat is very small.

So many small forces slowly gathered into big forces, and people gradually became stronger, and people at that time were still relatively united, helping each other, and resisting the changes and dangers that occurred in the world together.

These 300 shelters were built at that time, when people's scientific and technological strength was very weak, and it took a lot of manpower, material and financial resources to build these three shelters, and many people even paid the price of their lives.

When these 300 shelters were first built, there was actually only one wall, and inside the walls were built ordinary brick houses like those in market towns today, and people took refuge from danger inside the walls and then worked outside.

When they encountered some invincible danger, they hid inside the walls.

Later, with the continuous development of science and technology, more and more houses were built inside the city walls, and the continuous planning and renovation slowly led to the prosperity it has today, and then people began to compete with each other.

The first half of the book is about the historical development process of mankind after the catastrophe, but the second half is about some disputes between human beings for power and status after the development of science and technology.

As the number of houses in the city increased, the population gradually flourished.

In fact, it is not prosperous, since the initial construction of the Acropolis, the population has been declining, and the population has been declining for the last three hundred years.

At that time, the medical conditions were not very developed, the mortality rate after birth was very high, and it was difficult for children to feed adults, coupled with the limitations of the environment at that time, and some degradation of physical functions after the evolution of people themselves.

So the birth rate during that time was very low, and many children did not reach adulthood, so year after year, the total population was getting smaller and smaller.

At its lowest, the total number of people in the 300 shelters was about 10 million.

At that time, technology had not been developed, or rather recovered, and people were at risk of extinction, although they were protected by the tall walls of the shelter.

But then someone accidentally found the ruins of a pre-cataclysmic city, found something in it, and then analyzed it by some top scientists, and technology developed rapidly.

The first thing that came was antibiotics, and the advent of these agents immediately increased people's survival rates a lot, and the population began to grow gradually, and there was a rapid explosion of growth.

In the last 100 years, the original technology has developed from almost nothing to the current situation, which is still very rapid.

Of course, it is also because people have mastered this method and rummaged through the ruins to find the records of previous scientific and technological civilizations.

Some cultures can be passed down from generation to generation, passed down by word of mouth, and eventually recorded. But the more complex things must not be recorded by word of mouth, and there must be some books, some models, and some real teaching materials to make people understand him.

There were no universities before the shelter, because it was very difficult for people to survive at that time, so naturally they didn't have the spare energy to start schools, but later, after technology brought convenience to them, people began to pay attention to it and began to invest in the economy to build some universities, in order to revive science and technology.

And now, the results of those efforts have been shown for them.

With the development of science and technology, people have actually begun to enjoy a lot of convenience, just like the emergence of buses, which people couldn't do before.

In fact, this is also a lack of people's ability to create, because small vehicles are the models they have found to design and some process standards. However, we have not been able to find the technology for large vehicles, so we have not been able to design large vehicles.

But this also confirms the importance of people's vocational and technical learning, because only by allowing people to continue to learn can there be those so-called innovators who can change the times, and only the emergence of these people can promote the further development of the times.

For this wasteland that is almost in ruins, they are in desperate need of a few characters who can change the world.