I had a Yellow Jacket nest in one of my flower beds last summer. I thought they were nesting in the mulch but when they all left, I found out they were nesting in one of the vent cracks in the brick. I can just imagine what the inside of the wall looks like behind the brick
it's really rare for me to see a beehive that's a foot long much less 20 feet long .. dang ...
Luis is right .. it's a lucky thing it was a dog rather than a small child (sympathy for dog lovers not withstanding .. don't wanna suffer the ku'u hates dogs wrath too)