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.
According to Cayce, the Great Pyramid took 100 years to build and it, along with its counterparts the Sphinx and Hall of Records, were built 12,500 years ago!--a far cry from the 23 years and 4,600 years ago that modern Egyptologists believe.