When people think of Egypt, this is their first thought -- three symmetrical pyramids rising out of the sand. A monument to the past and man's ability to influence the future. In fact, the pyramids are considered by many to be the most famous landmark on the face of the Earth. What allowed the pyramids to survive the ravages of time and the elements is their unique position. On the border of two distinct climates -- the heat and arid conditions of the desert, and the warm, moist, fertile delta nearby. The delta was an incubator for the people that created these masterpieces. Their creation survived because the pyramids lie just beyond the delta -- actually on a limestone shelf out of reach of the flood waters that would otherwise have eroded the precious stone thousands of years ago. They are monuments to the emperors Khufu, Khafre, and Menkaure (also known as Cheops, Chephren, and Mycerinus). The largest pyramid was built for Khufu and is also called The Great Pyramid. When built, it was 755 feet on each side, and 482 feet tall; but time and the elements have reduced it to 449 feet high. In ancient measurement, the 755 foot figure is equal to 440 cubits. No one is sure exactly how many stones it took to build Khufu's pyramid since the blocks are not all of uniform size or shape. Estimates are around 2,300,000 blocks averaging 2½ tons a piece. Napoleon estimated that by dismantling the pyramids he could build a wall around France ten feet tall and one foot thick. Inside the Great Pyramid are a number of passages, and a burial chamber 394 feet below the surface. Some of the original passages have been sealed either accidentally or on purpose, but tourists can go inside. Wear very comfortable clothing you don't mind getting dirty, bring water, and expect to spend about an hour hunched over with your hands full of sand. For this privilege, you pay a fee. What you can't do for any price, however, is climb the pyramids. In the early days of Western exploration this was possible and considered a "must-do." These days, the number of visitors and accidents has turned this bit of bravado into a postcard pipe dream. You'll have to conquer the past some other way. The smaller pyramids also have passageways, but the networks are less extensive. What all the pyramids have in common is their orientation and construction. Each is built on the compass points with a temple facing the east. Their main structures are built from local limestone, but their façades are of limestone and granite from quarries far away. In spite of what photographs show, the pyramids don't exist on their own. They are part of a vast complex both ancient and modern. Each pyramid is flanked by smaller pyramids, often the burial places of queens, cemeteries, and pits carved into the rock in the shape of boats. At one time these held the boats that the buried kings would use in the afterlife. The remains of one boat are now in the Solar Boat Museum. Another one, perfectly preserved, was discovered in 1987. It was left in place, and reburied to be discovered by future generations. There are also causeways leading to the pyramids that were used for transporting rock from the Nile to the construction site. Once building was completed, these served as ceremonial pathways to the pyramids. Modern life has crept into the daily lives of the pyramids. Vendors clamor for you to buy Coca-Cola and ride a camel, and the suburbs of Cairo are now only a few hundred yards away. But modern technology has also brought an opera house to the grounds. And at night there is a light and sound show with the pyramids as the main actors. More than 80 pyramids were built in the area. Some of them collapsed, and in a tribute to the architectural know-how of the Egyptians, when a pyramid collapses, the stones fall outward, rather than inward so the burial chamber remains protected.

• Pyramid of Khufu: Built in 2690bc, 450 feet tall, 755 feet on each side, 51.5 degree angle. The largest stone structure on Earth.
• Pyramid of Khafre: Built in 2650bc, 448 feet tall, 705 feet on each side, 53.8 degree angle.
• Pyramid of Menkaure: Built in 2600bc, 218 feet tall, 354 feet on each side, 51 degree angle.
• Unknown spirits are said to haunt the Great Pyramid.
• 17 June, 2002 - A burial chamber is found near the pyramids. It contains the tomb of Neni Sut Wissert, who led the workers who built the pyramids.
• 15 September, 2002 - A small robot is sent into the Great Pyramid on an exploration mission. It's goal is to crawl down a passage too small for humans and knock down the door at the end. The event is carried live on television around the world. When the robot finally breaks through the door, it finds... another door.