An obelisk is a tall, four-sided, narrow tapering monument which ends in a pyramid-like shape at the top. Like Egyptian pyramids, which shape is thought to be representative of the descending rays of the sun, an obelisk 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 is generally used for other monumental standing inscribed sculpted stones.