The Waters of Fortune?
A large, castle-like structure, overlooking and surrounded by a water filled moat. The large arena inside the castle has a central pool that leads outside through underwater tunnels, and four towers rising up from the moat area provide passageways back inside. The mono, sand-colored texturing can make it difficult to judge distances, although there's a lot of lighting/shadow detail, which helps out. A second copy of the map is set up with portions of the lighting changing from daylight to night time over a period of minutes, leading to different styles of play. There's a couple of large viewing distance errors, so you'll need IZD on 68k machines.
Levels in map "The Waters of Fortune™":
The Waters of Fortune™
The Waters of Fortune™--Night and Day