A fortress of stone erupts from a square area, 120' on each side, that you can see within range. It must not have any buildings or other structures on it. Any creatures in the area are harmlessly lifted up as the fortress rises (Details on the structure can be found in the PHB). The keep is furnished and decorated however you like, and it contains sufficient food to serve a nine-course banquet for up to 100 people each day. Objects created by this spell (i.e. furniture) crumble to dust if removed from the fortress. A staff of 100 invisible servants obey any command given to them by creatures you designate when you cast the spell. Each servant functions as if created by the unseen servant spell.

After 7 days or when you cast this spell somewhere else, the fortress harmlessly crumbles and sinks back into the ground, leaving any creatures that were inside it safely on the ground. Casting this spell on the same spot once every 7 days for a year makes the fortress permanent.