In the Bruniquel cave, located in southwest France, scientists have uncovered evidence of complex structures built by Neanderthals around 176,000 years ago. These structures, made up of nearly 400 broken stalagmites, include a large circular arrangement with a diameter of about 6.7 meters, a smaller semicircular shape, and several organized piles. The constructions were found over 330 meters from the cave's entrance, in a part that is completely dark, and show signs of fire use and burned bones. This discovery is significant because it predates the arrival of Homo sapiens in Europe by more than 100,000 years, challenging previous ideas about Neanderthal capabilities. The age of the structures was determined using uranium-thorium dating, a method that measures the decay of uranium into thorium in the mineral layers that formed over the stalagmites. This dating technique confirmed that the structures are approximately 176,000 years old. The construction of such elaborate structures in total darkness suggests that Neanderthals had a level of planning and coordination comparable to modern humans. They would have needed to master fire and artificial lighting to navigate and work in the dark, as well as organize themselves collectively to transport and arrange the heavy materials. The purpose of these structures remains a mystery. However, the complexity of the construction indicates that Neanderthals may have possessed a level of ingenuity and organization that was previously underestimated. This discovery adds to the growing body of evidence suggesting that Neanderthals were more cognitively advanced than once believed. The Bruniquel cave was first explored in 1990 by cavers, but archaeological research was halted due to the early death of the lead archaeologist. The site remained largely uninvestigated until 2013, when a team from the University of Bordeaux conducted a comprehensive study, revealing the remarkable Neanderthal constructions hidden deep within the cave.