IF what you are actually looking for is the building with most floor that would have to be the magician tower in edron wich Edron which goes from -3 to +7 Source:https://tibiamaps.io/map#33266,31837,10:1 (at least thats the one with most floors i that's the one with most floors I could find) if find). If you are looking for the highest one there are several with that record since high is usually consider above ground and there are several buildings that are +7 floors also that only applies to buildings i I believe the are formations like caves or mountains that can go more that than, not many but at least one i can thinkI can think.