La Tène is the reference site of the European 2nd Iron Age. It yielded thousands of exceptionally well-preserved finds – mainly weapons and prestige objects – which were used to characterise the Celts and Gauls described in Greek and Latin literature. Its interpretation has been the subject of much controversy for over 150 years. Discovered in 1857 at the northern end of Lake Neuchâtel, this prolific site has been explored many times, most recently in 2003. The main operation took place between 1907 and 1917: on this excavation, which was then unprecedented in Switzerland, the excavators systematically cleared a former filled-in bed of the Thielle, over a length of 170 m, 40 m wide and up to 4 m deep. The site is interpreted as a sacred place of memory, in a symbolically charged landscape, where a monument was erected at the end of the 3rd century BC to commemorate a battle that has left no written record. Alongside two bridges over the Thielle, strategically linking the Jura and the Swiss Plateau, this monument, decorated with horses’ heads on pikes, served as a ritual display of weapons, ornaments and even the remains of warriors, surrounded by the bones of animals probably sacrificed during banquets celebrating the outcome of the battle. The variable topography of the shallows of the Bay of La Tène, often bathed in persistent mists, on a shifting boundary between land, sky and the fluctuating waters of the lake and river, can be related to a symbolism of the passage between life and death.