The word obelisk is derived from the ancient Greek word 'obeliskos' which means a pointed pillar. It is a narrow and elongated monument which has a pyramid like shape at the top. It is tall and has four sides. Ancient Egyptians called it 'tekhenu'. Greek who saw the monuments called them 'obeliskos'. Ancient obelisks were built with a single stone. But modern obelisks are made from several stones and will have space inside. Obelisks represented the Sun God 'Ra' and it is believed that God existed inside it. So they are usually placed in pairs at the entrance of the temple.