From the enclosure map of the village of Siim from 1783 you will see that it is located at the south end of large wetlands called the Gonggen (the Rumbling), in later times named Siim Mose (Siim Marsh).
One can speculate that the name Gonggen possibly refers to the soft peat soil that rumbled when you walk on it.
Siim Mose fills a wide hollow in the broken moraine country east of the huge melt-water glacial valley where the River Gudenå flows today. The large gully, where Bakkelyvej runs today, leads from a hollow towards the river, showing where ice once blocked the way, before slowly melting. It left a minor lake, which later became choked with bog moss and other plants. Later the gully of Bakkelyvej was used for driving the village’s cattle to the pastures at the river bank.
At several places around the marsh, house sites and graves have been found, providing evidence of settlement around the marsh since ancient times. Perhaps, the village of Siim was known as a”walking village” – meaning a settlement which changes location for example after a fire. Previously, village houses were closely packed, so when a fire began in one place it quickly spread throughout the entire village. Afterwards the village was then rebuilt in another place nearby.
In the mid 1990s, Ry Municipality completed a nature restoration project in the marsh. The ground water level was raised, so the natural flora and fauna could return. Today there is public access to the marsh by means of paths, and green walkways to other natural areas have been established.