Europe
In 2017, the population of Europe was estimated to be 742 million according to , which is slightly more than one-ninth of the world's population. This number includes Asian Russia (Siberia, about 36 million people) but excludes the European part of Turkey, Cyprus and the Transcaucasian countries.
A century ago, Europe had nearly a quarter of the world's population. The population of Europe has grown in the past century, but in other areas of the world (in particular Africa and Asia) the population has grown far more quickly. Among the continents, Europe has a relatively high population density, second only to Asia. Most of Europe is in a mode of Sub-replacement fertility, which means that each new(-born) generation is being less populous than the older.
The most densely populated country in Europe (and in the world) is the microstate of Monaco.
Hillfort
Prehistoric Europe saw a growing population. It has been estimated that in about 5000 BC during the Neolithic between 2 million and 5 million lived in Europe; in the Late Iron Age it had an estimated population of around 15 to 30 million. Outside Greece and Italy, which were more densely populated, the vast majority of settlements in the Iron Age were small, with perhaps no more than 50 inhabitants. Hillforts were the exception, and were the home of up to 1,000 people. With the emergence of "oppida" in the Late Iron Age, settlements could reach as large as 10,000 inhabitants. As the population increased so did the complexity of prehistoric societies. Around 1100 BC hillforts emerged and in the following centuries spread through Europe. They served a range of purposes and were variously tribal centres, defended places, foci of ritual activity, and places of production.