Dense is the opposite of Intelligent. Intelligent is the opposite of Smart. Smart is related to Human. you are likely to find Human in/at/on War. 
Expedition is related to Trip. Trip is related to Term. Term is related to Bird. Bird is related to Sky. 
Dense <--Antonym--> Intelligent <--Antonym--> Smart <--RelatedTo--> Human --AtLocation--> War 
Expedition <--RelatedTo--> Trip <--RelatedTo--> Term <--RelatedTo--> Bird <--RelatedTo--> Sky 