The tumulus of newgrange is a passage grave. It was constructed in the Neolithic period – app. 3200 BC. It thus is older than the Pyramids in Gizeh and older than Stonehenge and Woodhenge. The structure is 76m in diameter and up to 12m tall. From 1962 to 1975 a large scale archeological excavation took place and the monument was reconstructed to its current form. This reconstruction is controversial: Were the light cobblestones used to adorn the wall or did the serve as a pavement around the tumulus? The visitor center is where the guided tours start and where you can information about the tumulus, the Neolithic period, etc.