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.
Answer by Napo93. Confidence votes 2.2K. According to ''National Geographic'' it took an estimated 20,000 to 30,000 workers to build the Pyramids at Giza over a period of 80 years from about 2570 to 2490 B.C. and slaves were not used.