What are the three man-made structures visible from earth orbit without magnification?
- The Greenhouses of Almería, Romanian Parliament,The Kennecott Copper Mine
- The Nasca lines, The Great Pyramids of Giza, The Great wall of China
- The Great Pyramids of Giza, The Great wall of China, The monuments of Easter Island
- Great Pyramid of Giza, The Greenhouses of Almeria, The Suez Canal