I think you are forgetting that Egypt is part of Africa. The Egyptians were doing some impressive architectural creations while many Europeans north of Greece were living in huts.
Egypt (in the end conquered by Greece and then the Romans):
Timeline of Ancient Egyptian civilization:
c.5000 BC: The coming of farming to the Nile Valley
c. 3500-3000: The Pre-dynastic period, leading to the unification of Egypt
c. 2650: The beginning of the Old Kingdom
c.2575-2465: The Great Pyramids of Giza built
c. 2150: The fall of the Old Kingdom leads to the 1st Intermediate period begins
2074: The Middle Kingdom begins; Egypt is united and powerful again
1759: The fall of the Middle Kingdom leads to the 2nd Intermediate period, and the occupation of norhern Egypt by the Hyksos
1539: The reunification of Egypt and the expulsion of the Hyksos begins the New Kingdom, a period when Egypt became a leading power in the Middle East
1344-1328: The pharaoh Akhenaton carries out a short-lived religious reformation
1336-1327: Tutankhamen reigns
1279-1213: The reign of Ramses II brings Egypt to the height of its power
c. 1150 onwards: The New Kingdom falls into decline
728: Egypt is conquered by Nubian kings
656: Egypt is occupied by the Assyrians
639: The Egyptians expel the Assyrians and begin a period of revival
525: Egypt is conquered by the Persians
332: Egypt is conquered by Alexander the Great
305: Ptolemy, one of Alexander the Great’s generals, founds a Greek-speaking dynasty
30: Cleopatra, the last queen of independent Egypt in ancient times, dies, and Egypt is annexed by the Roman Empire
That Cleopatra wasn’t Egyptian at all. She was genetic Greek. And DNA indicates ancient Egyptians were closer to Middle Easterners than Egyptians are now. In other words, they had less sub-Saharan African DNA.
Some structures are pre-flood, the Sphinx and great pyramids among them.