A classic clip from 1981 shows a nimble man dancing upon a door that’s placed on the ground with four glasses filled with water on each corner of the door. The dancer tries not to spill any water from the glass as he performs a high stepping jig. This performance is known as the traditional art of Sean-nós or Irish Door Dancing, which has its roots in farming communities.
You see in the old houses they had only a mud floor in a lot of the old houses so when they’d be a gathering the people there to any kind of a function …the solo step dancer then would be asked to dance and the door would be taken down from him for him to dance on …and if there were two or three dancers that were very good and that they weren’t able to decide who was the best, they’d put them through the drill again and leaves four glasses around on each corner of the door and whoever was able to do is dance the best.
Here’s a more modern take on the dance.