<human>:  When did the Ice Age start and when did it end?
<bot>: The last ice age began around 20,000 years ago and ended around 10,000 years ago. During the last ice age, the earth was covered in ice up to two miles thick, and sea levels were hundreds of feet lower than they are today. This period of time was characterized by glacial ice sheets that covered most of the northern hemisphere, including North America, Europe, and Asia. During this time, the climate was extremely cold, and the average temperature was about 12 degrees Fahrenheit colder than it is today.