HDRI from the Dungeon of the Tourbillion Castle. This is the fourth part of the 5-part Tourbillion Series of HDRIs and Scene Files. The product includes a high, low and ultra-low resolution HDRIs, and a specular convolved one. 5 example renders are explained in a web browser compatible document and a video. Additionally, 11 Scene Files for this HDRI set are included to experiment with and take apart to see how they work.