A large black and white miniatures map with a simple, old school feel (compatible with one inch figure bases but can be scaled to suit).
The high-res map can also be used in your next publisher project if you prefer and the zip comes with the appropriate user license (use for commercial or personal but not as stock art)
Also included in this zip file: a player handout map matching the prison, but less detailed and a PDF containing the optional key and background for a prison scenario using the fortress map.
Also included is a blank labyrinth map for the GM to use in conjunction with the fortress, but which is also free to use as stock art for your next commercial or personal project.
Image sizes (in pixels):
Labyrinth map - 1003 x 846
Miniatures battle map - 9249 x 4289
Player handout - 1160 x 624