The Pleistocene featured ice age giants and the arrival of modern humans.

The Pleistocene epoch is a geological time period that includes the last ice age, when glaciers covered huge parts of the globe. Also called the Pleistocene era, or simply the Pleistocene, this epoch began about 2.6 million years ago and ended 11,700 years ago, according to the International Commission on Stratigraphy.

Modern humans, or Homo sapiens, evolved during the Pleistocene and spread across most of Earth before the period ended, according to the University of California Museum of Paleontology. The epoch also featured ice age giants, such as woolly mammoths (Mammuthus primigenius) and saber-toothed cats, many of which disappeared at the end of the Pleistocene in a major extinction event.

The Pleistocene was preceded by the Pliocene epoch and followed by the Holocene epoch, which we still live in today, and is part of a larger time period called the Quaternary period (2.6 million years ago to present). The name "Pleistocene" is the Latin combination of two Greek words: "pleistos" (meaning "most") and "cene," which comes from "kainos" (meaning "new" or "recent"), according to the Collins Dictionary.

The ice age peaked during the Last Glacial Maximum about 20,000 years ago, when glaciers covered vast swathes of North America, Europe, South America and Asia. At that time, global temperatures were about 11 degrees Fahrenheit (6 degrees Celsius) lower than they are today, according to a 2020 study published in the journal Nature.

Ice age conditions were also drier than today. Because most of the water on Earth's surface was ice, there was little precipitation; rainfall was about half of current levels. The sea level was much lower, and the shorelines were typically much farther out because glaciation trapped water in ice sheets, according to the American Museum of Natural History in New York City.

The last ice age is known for hosting many large mammals called megafauna. Mammoths, saber-toothed cats, giant ground sloths and mastodons roamed North America during this period, according to the Florida Museum of Natural History. But it wasn't just giant mammals. An 11-foot-tall (3 meters), flightless bird that weighed almost as much as a polar bear inhabited Europe during the early Pleistocene, Live Science previously reported. Meanwhile, Megalania prisca, the largest known terrestrial lizard, lived in open forests, woodlands and other Pleistocene habitats across much of eastern Australia during the epoch, according to the Australian Museum in Sydney.

Although plenty of Pleistocene animals are now extinct, much of the wildlife would be familiar to humans today. For example, alongside mammoths in Alaska, there were the same brown bears (Ursus arctos), caribou (Rangifer tarandus) and wolves (Canis lupus) as there are today, according to the National Park Service. On the other side of the world, in Western Australia, the remains of an ancient campfire discovered in 2018 suggest Aboriginal people held a kangaroo feast at the peak of the Pleistocene ice age about 20,000 years ago.