I figure this thing is 40 feet tall, not counting the roof, and about 21 feet diameter inside. That would mean it has room for 4 floors with 8 foot ceilings, and each floor would be about 346 sq ft (minus 16 sq ft for a spiral staircase).
I'd make the top two floors living space. The second floor storage space. And the ground floor a garage and workshop for my motorcycle with a 4-foot wide metal security door as the only entrance.
It would have great views of the surrounding countryside. The wide eaves would provide shade. The windows would provide plenty of cross ventilation. And it would be as private and secure as any house with windows can be.
Castle Tower.jpg