The greatest genocide in human history was the genocide of Indians. The entire continent was stolen during the Age of Discovery.

Photo by Matthäus Merian (licensed under CC0 1.0)

The biggest massacre in human history

The largest genocide in human history is said to be the Indian Massacre. It was an ethnic annihilation campaign said to be about 10 times more effective than the Nazis' genocide of Jews. There is no unified population register for the indigenous peoples of the Americas, so we estimated the population in 1492, and based on the difference between the numbers when it became possible to ascertain the population after the population had declined, we found that there was a risk of epidemics, cold weather, etc. Exclude factorial estimates. Below are some estimates of the indigenous population before settlement.

Population estimate in 1492

1964 Woodrow Boller estimate: 100 million people
1966 Henry Dobbins estimate: 90 million to 112.5 million people
1976 William Denevan estimate: 43 million to 72 million people
1992 Stannard estimate for 2019: 100 million people

The indigenous population declined by approximately 95% by the early 20th century. Ward Churchill estimated that the total number of Aboriginal deaths was slightly over 100 million.

worst human holocaust

David Stannard has called it "the worst human holocaust the world has ever witnessed."
https://www.se.edu/native-american/wp-content/uploads/sites/49/2019/09/A-NAS-2017-Proceedings-Smith.pdf

Cooling is caused by population decline

There was a conventional theory that the decline in the population of indigenous peoples was caused by the cold, but a research team from University College London in the UK found that the cause and effect were the opposite, and that the population did not decrease due to the cooling, but that the indigenous population decreased. As a result, forests grew naturally and the area increased, leading to cooling. The number of Indians massacred here is estimated at 56 million.
CNN article: https://www.cnn.co.jp/fringe/35132233 .html

Below is a list of massacres that took place only in North America. Of course, this is only a part of the whole.
https://en.wikipedia.org/

indians are asians

Indians are Mongoloid people who crossed the Bering Strait and are thought to be a people of Asian origin. Currently, the Americas include Canada, the United States, Mexico, Guatemala, Nicaragua, Colombia, Brazil, Chile, Argentina, Cuba, and Puerto Rico. There is not a single indigenous Indian country on that vast continent.