Rome is home to more obelisks than any other city in the world, a grand total of eighteen, including the world's largest. In addition to eight ancient Egyptian obelisks, there are five ancient Roman obelisks and five modern (19th & 20th century) obelisks.
Obelisks played a prominent role in the architecture of the ancient Egyptians, who first constructed them, placing them in pairs at the entrance of temples.
An obelisk is a square, tapering, monolithic pillar, which culminates in a capstone, known as a pyramidion. The pyramidion was usually sheathed in a bright metal, such as gold, gilded bronze or electrum, so that its facets reflected the moving sun. The four faces of the obelisk were typically adorned with hieroglyphs, which praised the glory of the pharaoh.
My Google Map showing the location of all the obelisks in Rome.