Answer: Baltic Sea
Notes: Three Russian MiG-31 fighter jets violated NATO member Estonia’s airspace over the Gulf of Finland for 12 minutes. The Gulf of Finland is the easternmost part of the Baltic Sea in Northern Europe, covering 30,000 sq.km. It extends 400 km east to west and 19–130 km north to south, bordered by Finland, Russia, and Estonia. Capitals Helsinki (Finland) and Tallinn (Estonia) lie on its shores, with St. Petersburg at the eastern end. The gulf is shallow, average depth 38 m, low salinity (6‰), and freezes 3–5 months in winter. It receives Neva and Narva rivers and the Saimaa Canal.
