[History] Why can't we know well about past civilizations?

It is because records of past civilizations have not been preserved. 

In 1966, during the Cultural Revolution, Mao Zedong burned valuable ancient books including Confucius's "Analects," which had nothing to do with communism. 

When Kim Il-sung took power in North Korea in 1945, he burned major books to give "simple minds to simple people," and Hitler also burned books that were important historical materials in 1936, in front of many people. Regrettably, teacher Paul also burned important books about all past civilizations in Ephesus after converting from paganism to Christianity.

Pachacuti, the 63rd Inca ruler, burned books containing records of all civilizations that were 5,000 years old, and the Library of Alexandria in Egypt had 50,000 volumes on human civilization, but they were lost to invaders.

In particular, an invader named Caliph Omar used precious books containing amazing stories of human civilization as fuel for heating public baths. 

The 200,000 valuable books housed in the Jerusalem Library were burned by religious fanatics, and Emperor Qin Shi Huang, who unified China, burned more than 50,000 precious books.

"Collect and burn all books except medical books, books on agriculture, and the history of the Qin dynasty, which are essential for the people."

We who live in the 21st century buried two time capsules in a certain area of New York in 1965 for the next generation. These capsules are made of metal stronger than steel and will not melt even in an atomic bomb. Inside, we put micro-productions of everything from our civilization.