The Ground Floor, now accessed through the recently added spiral staircase, would have originally been used for storing ammunition and supplies. The magazine room, used to store gunpowder, features "pizza oven" shaped holes, which are vents up to the top. This would have provided the ventilation and airflow needed to help keep the gunpowder dry. The original copper-covered door remains in place to this day, a safety feature to prevent sparking near gunpowder.
Underneath the brick flooring, accessed via two hatchways with wooden covers is a smaller cistern area (which is up to 1.2m deep). This would have been used as both a water-tank (supplemented by a rainwater collection tank) and storage for food, although this does not continue under the magazine area.
Evidence of the Tower's use as a puppet museum is seen with the display cabinets on the ground floor and the bright paint on the spiral stairs leading down. There was also a door inserted, out to ground level, but this was blocked off.
Sources: wishtower.org.uk, Wish Tower Conservation and Management Plan (Wish Tower Friends, ExtraVerte Community Projects), Historic England List Entry