The Grotte de Spy (Cave of Spy) is one of the most important paleolithic sites in Europe, and has undergone many excavations with many recoveries. In 1886 a discovery was made that still represents a capital episode in the history of science. The excavation was conducted by inhabitants of Liège, and consisted of an archaeologist (Marcel de Puydt), a geologist (Max Lohest) and a paleontologist (Julien Fraipont). This team proved to the international community the existence of a more antiquated type of human, the Neanderthal. Julien Fraipont published a major review about Spy in an American review.
The prehistoric cave may be freely visited all around the year. However, between mid September and February there is hunting season, and visitors are advised to be careful.
The cave may be visited on guided tours organized by the Amis de l'Homme de Spy (Friends of the Spy Man), a non profit organization. The guided tours have a fixed price for the guide and are suitable for up to 30 persons. See web site for more details.