What capital city in Europe has the highest or largest urban concentration of over 10,500,000 people which makes it the sixth largest city in the world?

Moscow, Russia.

Explanation:

Moscow is the capital city of Russia. It has an estimated population of 10,500,000 people with a very low density per square mile. It is the second most populated city in Europe behind Istanbul, Turkey. The name Moscow is often thought to be derived from the Moskva River.

It has one of Europe's largest economies, and low living costs compared to other major cities.

it depends on which society you are referring to. many civilization performed rituals so the gods would with their growing season but the most well known is that of the aztecs. they would make sacrifices, usually animals, but sometimes humans as well.