Daugavgrīva (German: Dünamünde; Polish: Dynemunt; Russian: Усть-Двинск or Ust`-Dvinsk) is a neighbourhood in North West Riga, Latvia on the left bank of Daugava river. In this neighbourhood there is located Swedish built strong fortress commanding the mouth of the Daugava on the left bank of Daugava.Fortress
On the opposite side of Daugava (German: Düna), outside the borders of the contemporary neighborhood, in 1208, there was built Dünaburg castle by the Teutonic Knights which initially served as a monastery. The Swedish fortress of Dünamünde, designed in a Dutch style by General Rothenburg in 1641, replaced the ruined Daugavgrīva Castle by 1680.
In 1695 the Commandant was captain Heinrich Nicolaus Rüdinger, forefather of future Patriarch Alexy II of Russia. Rüdinger was knighted by Charles XI of Sweden.Joachim Cronman later became the Commandant and he died on March 5, 1703.
After the fortress was seized by the Russians they reconstructed it. Regent Anna Leopoldovna of Russia, her husband Anthony Ulrich, and her son Ivan VI were incarcerated in Dünamünde in 1742.
A local Lutheran church was rebuilt into the Orthodox Church of the Saviour's Transfiguration in 1775.
The Russian government renamed the fortress, where only Russian soldiers were living, to Ust-Dvinsk in 1893. They had its fortifications completely reconstructed prior to World War I. During the war Ust-Dvinsk was bombarded by the Schütte-Lanz Airship SL 7 of the German Army. After the fortress was taken by Imperial Germany, it was inspected by Emperor Wilhelm II in 1917. The Latvian government, however, demolished much of the fortifications several years later. During the Cold War Ust-Dvinsk was a base for Soviet troops. The site is now known in Latvian as Daugavgrīva. There is a functional lighthouse at Daugavgrīva which was originally built in 1818. It was rebuilt in 1863, 1920, and after World War II.