Quercus Robur
The oak is the most iconic tree of northern Europe, easily recognizable by its typically shaped leaves and its acorns. Oaks grow slow, but they can grow old, large, and very impressive.
In many a folk history, stories are known about the use of an oak as canopy under which sermons or other get-togethers were organized by local people. So beloved is this tree, that individual oaks have been mentioned throughout history. One of the best known is the Hairlop oak in Hainault Forest, which had a girth of around 11 m, with branches spreading to about 90 m in circumference. Many celebrations and other happenings took place beneath its boughs. The tree doesn’t exist anymore, but is still well known in local folklore.

A Gathering under the Fairlop Oak, around 1790. Maker of this engraving not known by me. Note that the tree, which was taken down in 1820, already holds many dead branches.
Sources
Escot, Brian et al. Hainault Forest Website.
Mrs. M. Grieve. A Modern Herbal.