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.
There are three pyramids in Giza~   The Pyramid of Menkaura: 213 feet tall  The Pyramid of Khaefra: 471 feet tall  The Great Pyramid of Khufu: 481 feet tall   The Gâ¦reat Pyramid of Khufu is the tallest pyramid in Giza  and throughout Egypt.