Here is an example 5 Room Dungeon to inspire your contest entries. In your campaign, you’ll need to flesh out some of the details, but this skeleton format is perfect for GMs to pick up and customize for their own memorable sessions.
The Dragon Isles consist of no less than thirty or so separate islands, of varying sizes, in a fifty-mile chain running on an approximately north-south line about thirty miles off of the eastern coast.
A basin type hole in the middle of the plains. Once every so many years the rains come very hard and flood this place. Maybe that is where the tribes congregate for their tribal meetings.