History, culture, persons, nations, societies
A note: don't mix the ethnicities, language groups, genetics of human populations, culture, and other concepts. These are different things and English/French/German/Russian/Chinese/Japanese/Turkish/etc. can mean: language, culture, ethnicity, genetics, etc. and these are (sometimes very) different topics. People learn languages, new cultures and have families with people from other languages, ethnicities, cultures, genetic backgrounds...
- Historical revisionism: “History is a continuing dialogue between the present and the past. Interpretations of the past are subject to change in response to new evidence, new questions asked of the evidence, new perspectives gained by the passage of time. There is no single, eternal, and immutable "truth" about past events and their meaning. The unending quest of historians for understanding the past—that is, "revisionism"—is what makes history vital and meaningful.” historian James McPherson. E.g. change in notion of: The "Dark Ages", concept of "feudalism", alchemy as contributed to chemistry, ..., WWI, WWII (German guilt or no guilt)...
- List of ongoing armed conflicts: current biggest: 1. Russo-Ukrainian War. Others: Syrian Civil War, Afghanistan conflict, Mexican drug war, Yemeni civil war (ex-Yemeni Crisis), Ethiopian civil conflict, Internal conflict in Myanmar, 2023 Sudan conflict, Tigray War.
- List of wars by death toll: 1. WWII. Others: WWI, Transition from Ming to Qing, Mongol invasions and conquests, An Lushan Rebellion, Conquests of Timur, Three Kingdoms War. The biggest density (currently PRC, China) caused the most deaths in most of the wars - 4/8 big wars were exclusively Chinese-only wars / 'civil wars'.