The history of China spans thousands of years, beginning with the emergence of the Xia Dynasty around 2070 BCE. This was followed by several significant dynasties, including the Shang and Zhou, which contributed to early Chinese culture, philosophy, and governance. The Qin Dynasty (221-206 BCE) is notable for unifying China and establishing the first centralized imperial government. Over the centuries, China experienced periods of prosperity and turmoil, marked by the rise and fall of dynasties such as the Han, Tang, and Ming. The Qing Dynasty, which lasted until the early 20th century, was the last imperial dynasty. In 1949, the People's Republic of China was established, leading to significant social and economic changes.