Obelisco di Montecitorio

The Obelisk of Montecitorio also known as Solare, is an ancient Egyptian, red granite obelisk of Psammetichus II (595-589 BC) from Heliopolis. Brought to Rome with the Flaminian obelisk in 10 BC by the Roman Emperor Augustus to be used as the gnomon of the Solarium Augusti. Augustus erected it as the gnomon of the Solarium Augusti, his giant sundial (or horologium) in the Campus Martius. The meridian, worked out by the mathematician Facondius Novus, was placed in the center of a surface measuring 160 by 75 metres (525 by 246 ft), constructed from slabs of travertine, on which a quadrant was marked out with bronze letters, with indications of the hours, months, seasons and signs of the zodiac