An Ice Age is a period in Earth's history when large areas of the planet were covered by ice sheets and glaciers. These cold periods are characterized by lower global temperatures and significant changes in climate. Ice Ages can last for millions of years and are often followed by warmer interglacial periods. The most recent Ice Age, known as the Quaternary Ice Age, began around 2.58 million years ago and continues today. During this time, the Earth has experienced several glacial and interglacial cycles, leading to the formation of features like glacial valleys and moraines. These changes have greatly influenced the planet's landscape and ecosystems.