Sinimäed Hills

The Sinimäed Hills (or Blue Hills; Estonian: Vaivara Sinimäed) are three linked hills in northeastern Estonia. The heights which are aligned west-east, consist of Tornimägi, Põrguaugu mägi (also known as Grenadierimägi) and Pargimägi (also known as Lastekodumägi). They lie in Vaivara municipality near the coastal town of Sillamäe in Ida-Viru County.

The hills are best known as the location of the Battle of Tannenberg Line, fought in World War II on July 26–August 12, 1944. There, the Waffen-SS defeated a Soviet offensive against Germany.

The Sinimäed hills are gently sloping mounds rather than mountains. Nevertheless, the hills are a dominant landform in the area - the height of the surrounding limestone plateau is on average 30 m above sea level, while the hills are up to 50 m higher. Pargimägi and Põrguaugu mägi are the two higher hills - 85 and 83 m, respectively, while Tornimägi is somewhat lower, 70 m. The ridge is about 3 km long.

The location of the hills on a 5 km wide strip between the Finnish Gulf and the woods and bogs of Alutaguse is the origin of their strategic importance. Tallinn-Narva highway (E20) passes the hills from the north and Tallinn-Tapa-Narva railway from the south.

The hills have at their core huge blocks of limestone, but their geological origin is not clear. They are believed to be formed either by continental glacier (terminal moraine) or by clay diapirs, or by the combination of both factors.

The western hill, Tornimägi, had an outpost during the Great Northern War.

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