Irminsul

Irminsul was an oak venerated by the pagan Saxons and which was said to connect heaven and earth. The Old Norse form of Irmin was Jörmun and interestingly, just like Ygg, it was one of Odin's names. Yggdrasil was the oak or ash tree from which Odin sacrificed himself, and which connected heaven and earth. It appears, thus, that Irminsul may have been a material anchor for Yggdrasil among the pagan Saxons.

It was located near Eresburg castle, Paderborn, and was destroyed by Charlemagne, in 772.