I know how you feel, Galen. Our neighbour isn't as close as that, but he built what he calls a barn right plonk in the middle of our lovely view. He told us he was building a barn and had got permission, but it turned out to be a huge monstrosity.
He came round when they'd finished to return our scaffolding tower, which he had borrowed and I'm afraid I told him it was an eyesore. I don't think his wife ever forgave me as she'd designed it. We planted trees to block it out, and they've left now.