Exploring the deep ocean floor: Hot springs and strange creatures. The ocean floor is home to many unique communities of plants and animals. Most of these marine ecosystems are near the water surface, such as the Great Barrier Reef, a 2,000-km-long coral formation off the northeastern coast of Australia.
Quick Answer. Egyptian pyramids often took 10 years or more to complete. According to the Greek historian Herodotus, the Great Pyramid at Giza was built in 20 years by 100,000 workers and was meant to be a tomb for Pharaoh Khufu.
Introduction. Archaeologists believe Egyptâs large pyramids are the work of the Old Kingdom society that rose to prominence in the Nile Valley after 3000 B.C. Historical analysis tells us that the Egyptians built the Giza Pyramids in a span of 85 years between 2589 and 2504 BC.rchaeologists believe Egyptâs large pyramids are the work of the Old Kingdom society that rose to prominence in the Nile Valley after 3000 B.C. Historical analysis tells us that the Egyptians built the Giza Pyramids in a span of 85 years between 2589 and 2504 BC.