So have fun with this. You can click on the bookcase to teleport into the room below. The room is decorated in cool tiles and metal plating. You can perform experiments, lock people up, hang out, or watch the spring water flowing past.

All at an affordable price.

Thanks to nandake and MelanieSunshine for helping me model.

This mesh is by KLF:
"This next model is my second add-on Secret Cavern which you should be able to add to any room you already own. Be the envy of all your friends when you show them your wonderful room you just bought, but then surprise them when you take them down to your secret lair where all the fun starts. This model uses an elegantly styled Book Shelf as the default level room item, and when you click it, your Avatar is automatically transported to the lower level. In this model, I've added a full array of floor, wall and ceiling nodes so you can add extra furniture - 93 in total. This model has 24 avatar nodes conveniently placed within the model. Please Note: although the model has been equipped with these furniture nodes, the 3D engine doesn't know how to load items onto the unit if it loads after the other items - This is beyond my control and I guess we'll have to wait for the programmers to find a solution. P.S. If you find it inconvenient move the furniture back to the lower levels before you invite your friends, take a look at my next model which will be the same mesh in a full featured room version on an open space design."