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 Pyramids of Giza consist of the Great Pyramid of Giza (also known as the Pyramid of Cheops or Khufu and constructed c. 2560â2540 BC), the somewhat smaller Pyramid of Khafre (or Chephren) a few hundred meters to the south-west, and the relatively modest-sized Pyramid of Menkaure (or Mykerinos) a few hundred meters farther south-west.