Omonoia Square or Omonia Square (Πλατεία Ομονοίας Plateia Omonoias or Platia Omonias) is a square in Athens. It is served by a train station used by the Athens Metro and the Ilektrikos, appropriately named Omonoia Station. The square with 3 Septemvriou almost aligns to the north.
The square's traffic route from the 19th century until 1998 once more fully circumvented the centre with six streets, of which five also functioned as entrances and exits. From the 19th century to the 1950s, the area's layout more literally approached that of a square, framed by broad paths to the edges and centrally, and surrounded by neoclassical buildings. The square's focus also featured a shading arc of palm trees until the 1950s, and a central fountain until 2000, while almost a century ago, ceremonial cannon were once aligned in a central circle. The square including its trees were later and to great criticism demolished, except for the fountain, to make room for the ever-increasing traffic. The area now formed a pentagon facing northwest and greener hexagon to the northeast, with a central circle. Road areas continued to encroach on the previous design in the shape of a circle totaling four lanes, with part of the former road nevertheless transformed into a larger open pedestrian space; but to great regret half the neoclassical buildings in the western and northern areas were removed, although some neoclassical structures remain in the northern part and within Athinas Street.
Trees were later replanted within Omonoia, and encircled the fountain once again. When part of the square was shut down for renovation ahead of the Athens 2004 Summer Olympics, it was now decided to eliminate traffic from the west and east sides for good, reducing it to the westbound lanes at the southern section and the eastbound lanes at south leaving one route.
The focal space here has been argued to have existed since ancient times, later abandoned but revived when Athens became a city once more.
Sporting celebrations have recently been held here, including following Greece's victory in the Eurobasket 2005 finals and gaining of the champions title. Other sporting successes, such as at the Euro 2004 tournament, have also tended to be celebrated here.
On Omonoia Square two former hotels designed by the German-Greek architect Ernst Ziller in the late 1870s stand ; the "Bakeion" and the "Megas Alexandros"