Tables, chairs, groundsheet, tarpaulin, helmet, torch
Or Book indoor caving facility at a Scout Activity Centre & bring torches - helmets should be provided
In Scout HQ: Construct a linear cave using tables and chairs with groundsheet's and tarpaulins draped over the tables and chairs. Secure any legs of tables and chairs with ropes were they might move or could fall if raised up off the floor. The cave can be as long or as short as you wish. Cubs to wear helmets and use a torch to make their way through the cave.
Games to play
Once Cubs are confident, a leader could place items to find in the caving system such sponges, bean bags. foam shapes, (or for a spy camp, a film cannister with secret coded messages to be decoded once brough out).