He had originally intended that the museum be built under 2 miles of mountain and surrounded by 500 feet of steel, but had to settle for a less excessive construction plan. Security clearance procedures take 3 weeks, which discourages many visitors.
It housed the crown jewels, a technology display, and a famous royal puzzle in the form of a sandstone and marble maze. The technology display contains items generously provided by FrobozzCo International, such as a Temporizer, Pressurizer, and Room-Spinner. The Second Dungeon Master used that Temporizer to travel back in time to 776 GUE to steal one of the crown jewels. This resulted in a dramatic increase in security measures by Dimwit Flathead.
The theft of his royal ring no doubt led to a greater eccentric excessiveness on his part.