Lousberg

At 264 meters, the Lousberg is a prominent elevation on the northern edge of the historic center of Aachen, which was laid out as a forest and mountain park at the beginning of the 19th century according to plans by Maximilian Friedrich Weyhe. The origin of the name is not entirely clear. It could come from lousen ("to look"), since the mountain offers an excellent panoramic view, or it could be traced back to Louis the Pious, the son of Charlemagne. Another explanation has to do with the Aachen dialect term lous, which means "clever".

Geology, formation
Geologically, the Lousberg is one of Aachen's three witness mountains, along with the Salvatorberg and the Wingertsberg, and one of the southernmost foothills of the Aachen-Limburg Cretaceous. It was formed during the Upper Cretaceous, when the region around Aachen was affected by a Europe-wide marine transgression, during which initially sandy and later predominantly calcareous sediments were deposited (Aachen Formation). The morphological elevation of the Lousberg is related to the tectonic movements that led to the formation of the Lower Rhine Bight.

At the foot of the Lousberg, dark gray, clayey to sandy sediments of the so-called Hergenrath layers were deposited, which formed in a swampy river delta. Silicified wood, charcoal, and numerous concretions of marcasite are embedded in these layers. Due to the water-storing properties of the deposits, the clay of the Hergenrath layers forms the most important spring horizon in the region, both on the Lousberg and in the Aachen Forest.

Subsequently, during the Upper Cretaceous, the area was gradually submerged by the sea, and 30–50 m thick quartz sands of the Aachen Formation were deposited, which were mined in small sand pits on the lower slopes of the Lousberg (e.g. at the present playground at the end of Kupfer Street). There is a clear erosional unconformity between the sands of the Aachen Formation and the younger Vaals Formation of the Campanian. The sands of the Vaals Formation are characterized by an increased occurrence of glauconite. Because of their greenish-brown weathering color, these beds were formerly known as the Vaals Green Sands.

In the Campanian, tectonic movements began to increase, which are associated with the sinking of the Lower Rhine Bight and led to the uplift of the Lousberg Floe. The Vijlen and Orsbach limestones were probably not primarily sedimented due to their high altitude.

It was not until the Maastrichtian that the Lousberg floe was submerged again due to a rise in sea level. Dead microorganisms were deposited in a calcareous mud, which today forms the so-called Vetschau limestone. The original thickness of the limestone layer on the Lousberg was about 6 meters. The upper 4.5 meters contained layers of brown flint, which were the subject of a Neolithic quarry. All but a small amount of the flint was quarried, and the unused limestone material was dumped on the surrounding slopes. Due to the poor consolidation of this debris, small landslides still occur today, as evidenced by the uprooted trees and cracks in the footpaths.

Fauna and flora
From an ornithological point of view, the Lousberg is very rich in species, as studies carried out by the RWTH Aachen University have shown. The population of bats, amphibians, and reptiles is also remarkable. The amphibians find spawning waters in the Soers north of the Lousberg. There is a continuous yew forest on the plateau. In the former St. Raphael monastery park to the north, the listed Müschpark, there are extensive stands of wild daffodils.

History
During the Neolithic period, about 5,500 to 5,000 years ago, flint was mined and worked intensively on the Lousberg. This gray flint, easily recognizable by its characteristic chocolate-brown color zones, was used to make axes and other tools, most of which were polished on-site or brought to settlements as semi-finished products.

The striking coloration of the Lousberg flint makes it a suitable object for studying the distribution of axe blades. The 14C dates of the artifacts found in the Lousberg overburden indicate that the mine was in operation between 3500 and 3000 B.C. Calculations based on the volume of the overburden, the weight of the production waste, and the average weight of the axe blades suggest that about 300,000 axe blanks left the Lousberg. These axe blanks were distributed as far as Belgium (Thieusies, about 160 km by air), central Hesse (Büdingen, about 225 km by air), and eastern Westphalia (Neuenknick near Minden, about 280 km by air).

The Stone Age mining of flint has almost completely reclaimed the central plateau of the Lousberg, which originally consisted of a 6 m thick layer of calcareous limestone. The resulting dumps, up to 4.5 meters thick, are still visible today as a hilly landscape under the yew grove. Finished axes and flint flakes have been found in the area and on the steep slopes.

During the Roman occupation, the limestone was used to build the thermal baths of Aachen, and in the Middle Ages, it was used in the construction of Barbarossa's Wall.

At the beginning of the 19th century, the Napoleonic geographer Jean Joseph Tranchot began the topographic survey of the Rhineland at the scale of 1:20,000, starting from a triangulation point on the Lousberg. On October 17, 1807, the French Ministry of War erected a bluestone obelisk in honor of Tranchot and his colleagues, based on a design by the engineering geographer Capitaine Boucher. The obelisk is a precisely measured central point that served as a starting point for astronomical observations and mapping in the region. From there, other points in the area were determined using the triangulation method, which eventually allowed the entire area to be mapped. When Napoleon was deposed on April 2, 1814, the monument was destroyed. On May 15, 1815, the obelisk was re-erected by order of the Prussian Baron Karl von Müffling, who continued the surveying work on behalf of the Kingdom of Prussia. The inscription praising Napoleon was replaced by the inscription that can still be read today. The damage to the edges of the stone was compensated by chamfering, which is untypical for an obelisk.

Legend
The Lousberg legend, one of the Aachen legends, explains the existence of the Lousberg as a single mountain in the middle of the Aachen basin in an etiological way.

According to the Aachen Cathedral legend, the people of Aachen tricked the devil into building the cathedral. The devil was out for revenge and wanted to bury the cathedral and the city in the sand forever. However, he was tricked by a poor woman and dropped the pile of sand north of the city, creating a larger and smaller mountain.

Because the woman was "lous", which means "clever" in the Aachen dialect, the larger mountain was called "Lousberg".

The legend is commemorated by a group of bronze statues on the Lousberg, depicting a farmer's wife and a devil, created in 1985 by Aachen artist Krista Löneke-Kemmerling.