The ancient history and origins of the pyramids have been a great puzzle throughout the ages. Many of the world's great leaders have visited these mysterious works of engineering, from Julius Caesar to most recently, President Barack Obama.

The first ancient egyptian pyramid was built in Saqqara, Egypt. It was constructed for the Pharaoh Djoser in 2630 BC. It started out small but as his reign continued he had it built larger and larger until it reached a height of 204 feet. This made it the largest building in the world at the time.

The biggest ancient egyptian pyramid ever built was The Great Pyramid of Giza. It stands at 481 feet tall and incorporates approximately 2.3 million blocks of stone. It was built for Pharaoh Khufu. This is the famous pyramid that everyone who visits Egypt want to clamber inside. It still stands today, joined Khufu’s son’s pyramid, The Pyramid of Khafre. Out of deference to his father, Khafre built his pyramid to be only 471 feet, just shorter than his father’s great tomb but he made up for it in the technical complexity of the design.

Construction of Pyramids continued for centuries, the last one being built for the Pharaoh Pepi II in 2250. His pyramid was much smaller, only 172 feet tall was of inferior construction, signaling the end of a great ear.

Everyone knows that the pyramids are old. The Great Sphinx, also old. This, however, is where the agreement ends.

Modern scholars, academics and Egyptologists accepted that the Great Sphinx was built during the same time period as the Giza Pyramids, most likely during the reign of Khafre. The Sphinx is a great cat with a human head, although these days it is missing its nose. Legend has it that Napoleon and his troops shot it off during their invasion, but historians have noted that Arab invaders in the 15th century also reported the nose missing.

However, despite the Egyptologists claiming that the Great Sphinx was built during Khafre’s rule, there has been great debate about it in the scientific community. Geologists studying the Sphinx discovered erosion marks on its body that could not be explained by wind or sand. Looking more closely, they discovered that the erosion marks were most likely created by vast volumes of water.

Egypt is know for its great deserts and predictably dry, hot weather. How could the Sphinx, if built around 3500 years ago have gotten water erosion? The answer, many scientists believe, is that the Sphinx was actually built during the last period that Egypt had regular rainfall – approximately 15,000 to 10,000 BC.

Egyptologists staunchly deny this idea, claiming the science is inaccurate, but most geologists and other scientists hold it as evidence that the Sphinx was not built during the time of the great Pyramids.

Whatever your take on the mystery, The Sphinx and the Ancient Egyptian Pyramids of Giza are a breathtaking spectacle of human achievement. Entrance to the Pyramid of Giza is now limited to 150 people per day and they don’t take reservations, so get there very early in the morning to have a look inside. Most hotel in Cairo can arrange a ride and a guide with about 24 hours notice.