The Leaning Tower of Pisa is well-known for its tilt, and while it's a beautiful structure, it's unlikely it would've received such world fame without the poor foundations that caused it to sink and tilt. However, it seems unlikely that the tower's tilt was as appreciated by the original builders and commissioners as it is by the modern folk, because they'd have no way to foresee its eventual fame as a landmark.
When did the characteristic lean become seen as an appealing feature of the tower, instead of just being a botched result of bad workmanship or architecture? Or has the tilt been always accepted as an "emergent feature"?