The Great Pyramid of Giza, also known as the Pyramid of Khufu or the Pyramid of Cheops, was built during the reign of the Egyptian Pharaoh Khufu. Khufu was the second pharaoh of the Fourth Dynasty of the Old Kingdom of Egypt and ruled from around 2589 to 2566 BCE. He was the son of Pharaoh Sneferu and is believed to have reigned for about 23 years.

Khufu's reign is considered to be a significant period in Egyptian history, particularly because of the construction of the Great Pyramid of Giza. This pyramid is the largest of the three pyramids in Giza and is one of the Seven Wonders of the Ancient World. It was built as a tomb for Khufu and is believed to have been completed around 2560 BCE.

The construction of the Great Pyramid of Giza required immense resources, labor, and engineering skills. It is estimated that it took around 20 years to complete the pyramid, with thousands of workers involved in its construction. The pyramid is made of limestone blocks, which were quarried and transported to the construction site. The blocks were then carefully stacked to form the pyramid's structure.

The Great Pyramid of Giza was originally covered with a smooth outer casing made of white limestone, which would have made it appear even more impressive and majestic. Over time, much of the outer casing has eroded or been removed, revealing the rough blocks underneath.

The purpose of the pyramid was to serve as a burial monument for Khufu and to ensure his safe passage into the afterlife. The pyramid was designed to protect and preserve the pharaoh's body and belongings, as it was believed that he would continue to rule in the afterlife.

In addition to the Great Pyramid of Giza, Khufu is also associated with other construction projects, including the Sphinx, which is believed to have been built during his reign. The Sphinx is a large stone statue with the body of a lion and the head of a human, thought to represent the pharaoh himself.

Overall, the Great Pyramid of Giza is a testament to the remarkable engineering and architectural skills of the ancient Egyptians, and its construction during the reign of Pharaoh Khufu is a testament to his power and influence in ancient Egypt.