Omonia station is an underground station under the Omonoia square of Athens, used by Athens Metro lines 1 and 2.
The first station opened 1895 but had been completely redesigned until 1930 as an underground Metro station. In 2000 the additional platforms for Line 2 were opened.
Wikipedia https://en.wikipedia.org/wiki/Omonia_metro_station
Address 18 Πλατεία Ομονοίας, Αθήνα 10551, Greece
Coordinates 37°59'2.806" N 23°43'40.764" E