An obelisk is a tall, four-sided, narrow tapering monument which ends in a pyramid-like shape at the top, and is said to resemble a petrified ray of the sun-disk. A pair of obelisks usually stood in front of a pylon. Ancient obelisks were often monolithic, whereas most modern obelisks are made of several stones and can have interior spaces. The term stele (plural: stelae) is generally used for other monumental standing inscribed sculpted stones. Obelisks were prominent in the architecture of the ancient Egyptians, who placed them in pairs at the entrance of temples. The word "obelisk" as used in English today is of Greek rather than Egyptian origin because Herodotus, the Greek traveller, was one of the first classical writers to describe the objects. A number of ancient Egyptian obelisks are known to have survived, plus the "Unfinished Obelisk" found partly hewn from its quarry at Aswan.
Contributions by Mervyn, Wetman, and David Haslam.