In ancient times these walls had a different purpose. They are well preserved to our time. Being in this park you can plunge into the atmosphere of the past.
Now these walls have a different meaning. Basically they are a "monument" to the memory of the past. And it's a good place for pigeons :)

Sometimes I wonder, why the human ability to hurt own kind, led to extensive progress in our history? The most important inventions were first used to kill people then only later on adopted for good causes.

This is a sad truth. And the truth is that humanity is the main threat to humanity and the planet. If there are extraterrestrial civilizations (and science says that this is so) then they will not come into contact with us for a long time. Humanity lives in a constant readiness for military action and in constant wars. I read that

Scientists have calculated that over the past 50 centuries, the peoples survived 14 thousand 500 large and small wars. For all the years of human existence, only 300 years have been absolutely peaceful.

That is why many scientists are afraid that artificial intelligence (when it will be created) will really declare war on humanity's main enemy - humanity. Paradox. But a fact.