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.
The Giza Pyramids, built to endure an eternity, have done just that. The monumental tombs are relics of Egypt's Old Kingdom era and were constructed some 4,500 years ago. Egypt's pharaohs expected to become gods in the afterlife.is Great Pyramid is the largest in Giza and towers some 481 feet (147 meters) above the plateau. Its estimated 2.3 million stone blocks each weigh an average of 2.5 to 15 tons. Khufu's son, Pharaoh Khafre, built the second pyramid at Giza, circa 2520 B.C.