While Africa appears to stand out, the truth is that pre-history over most of the world is full of question marks.
North America, South America, Africa, Australia, big chunks of Asia, often more is not known than is known.
One of my favorites is that prior to the European arrival, the northern and southern US tribes had a war so ferocious and extended that they ended up making what is now almost the entire state of Kentucky a “neutral zone”. And yet archeologists have just hints of what could have been comparable to the 30-Years War.
And, for another example, satellites have recently revealed that there is the equivalent of Hadrian’s wall in Africa, surrounding an ancient kingdom perhaps the size of Germany.
I’ve had the pleasure to hoof around the ancient city of Tikal in northern Guatemala, that they have been restoring now for a little more than 100 years. And those folks took engineering seriously. The tour takes about 4-1/2 hours of mostly walking.
The bottom line is that the preservation of knowledge in Europe was really the exception instead of the rule. And even there is pretty modest.
The accomplishments in Mexico and Central America are impressive. I spent hours walking around Teotihuacan near Mexico City, and Monte Alban and Mitla near Oaxaca, Mexico. The ruins further south are equally impressive. No wonder we have so many illegal immigrants from those areas in the construction trades. It is in their blood and heritage.