Sentence:  The first are the pit toilets — “<WSD>thunderboxes</WSD>” — boxes painted white inside, centrally located in various sections of the campground. The second type of toilet looks like a <WSD>thunderbox</WSD> but houses an odour-free flushing toilet. 
Meaning of the word marked with <WSD> tags:  An outhouse or latrine: a rudimentary outdoor toilet.