In the small town of Pļaviņas, at the place where the Skanstupīte River flows into the Daugava (Friendship Park), there are the remnants of a set of small and low fortifications known as the Swedish bastions. This was a place of military and political importance, because here was the place where the boundaries of Vidzeme (under Swedish rule), Latgale (under Polish rule), and the Duchy of Kurzeme (on the opposite side of the river) all came together. In 1625, the Swedes were defeated by the Poles here, and Swedish King Gustav Adolf almost lost his life. Medieval bastions of this kind can be seen in some other places of Latvia, as well.

The Bauska Castle contains a collection of cast iron cannons which date back to the latter half of the 17th century and the beginning of the 18th century. They were manufactured in the Duchy of Courland. The cannons that are in the garden of the castle were not found there – they were found in different locations in Zemgale. Four of the largest cannons came from Jaunsvirlauka, where they were found on the banks of the Lielupe River opposite Emburga. They are the best preserved weapons of their type in Latvia. The only cannon that was found in the castle itself is currently in its South-eastern tower as a thematic exhibit. When it was being cleaned, two cannonballs were found in the weapons. The local Livonian Order castle is in ruins, but it and its defensive structures, including earthen ramparts that were installed from the mid-15th until the early 18th century, represent an important element of Latvia’s military heritage.

In Soviet times, the border guards of Ventspils established a major complex of buildings, open areas and various objects. Most of these are no longer in use, and the area is not under guard.