In 1561, Reval was captured by the Swedes. In those days the city was a very vulnerable target, and therefore the rulers who came to these lands decided to strengthen it by building earthen ramparts. Thus, by 1710, three bastions had been built in Reval: Skoone, Ingermanland, and the Swedish Bastion. However, after the Great Northern War, which was lost to the Russians, these fortifications were never again used for their intended purpose.
One of the most outstanding bastions preserved to this day is the Swedish Bastion. It is located on the southern side of the Old Town and is a pentagonal earthen rampart. On the outside it is reinforced with massive stone walls, and inside it underground labyrinths were laid out, through which soldiers once moved unnoticed by the enemy, carrying weapons and ammunition. Today these underground passages house a historical museum, which can be entered through the Kiek in de Kök tower.
