Something that’s really unpleasant to look at is an eyesore. You could call your apartment building an eyesore if it’s a huge, ugly concrete structure that looms over your street.
Most eyesores are structures or buildings — an old, decrepit house that’s sagging on one side and has a yard full of weeds is probably thought of as an eyesore by most of its neighbors. You might also describe a new hotel as an eyesore if it’s painted a strange shade of pink that clashes with the buildings nearby. The word eyesore has been around since the 1500’s, from the idea of “something so offensive to the eye that it hurts.”