There are elevators, many doors at just one place that differ in size, the tunnels are extremely curved and there is one big empty room, where above Klownzilla is. There is one room that Mike and Debbie had come into, where purple lightning was occuring from a round electricity core. Mike states it smells like candy. There is a factory-like room that is the Killer Klowns' main laboratory filled with popcorn tubes, cotton candy cocoons hanging just like butchered meat on hangers, popcorn tubes where popping happens just like in electronic popcorn machines.
in the Film
The Big Top came in the guise of a shooting star and landed in a farmer's backyard outside the sleepy California town of Cresent Cove when he didn't notice until the beginning of the film. The farmer and his dog went to investigate, then were killed and trapped inside cotton candy cocoons by Jumbo. Mike and Debbie had came inside out of curiosity to check it. Later on, at the end of the film, the Big Top takes off and heading back to outer space, but it ultimately exploded when Klownzilla exploded inside it, killing all the killer klowns.