a blot on the landscape
Something that is considered unattractive that covers up or otherwise takes away from the value of something attractive. Although many people say that they want clean energy, they argue that miles of turbines on wind farms are a blot on the landscape.
blot on the landscape
Fig. a sight that spoils the look of a place. That monstrosity you call a house is a blot on the landscape. You should have hired a real architect!