The mysterious 2000ft height limit by the FAA.
The FAA cares about the efficient use of airspace. Believe it or not you can exceed it and there are structures that have applied to the FAA and received permission to build in excess of 2000ft tall. I believe in all cases these have been
guyed masts and not habitable structures, but I believe that's because there isn't market demand for a 2000ft structure yet.
Take a look at this letter-
https://oeaaa.faa.gov/oeaaa/external...etterID=159706
It explains the process.