The term "Ancient World" refers to a period in human history that spanned from around 3500 BCE until approximately 500 CE. During this time, civilizations such as those in Mesopotamia, Egypt, Greece and Rome developed their own unique cultures, religions, governments, art, architecture, science, technology, and literature. The phrase "Ancient World" is often used to describe the collective experiences of these various ancient societies, including their achievements as well as their challenges in areas such as warfare, trade, and social organization.