Used to be an office tower in Atlanta that had a visible lean. The ‘experts’ claimed it was just an optical illusion. But they demolished the building after only 25 years of use, highly unusual for an office tower. (As a side note, it cost as much to demolish it as it did to build it, as it had to be carefully deconstructed floor by floor.)
A simple bubble level could have proved them wrong. Even used as a plumb bob.
Of course, a laser...