Touchdown is a type of Landing. you are likely to find Landing in/at/on Airport. 
Nightmare is related to Street. Street is related to Neat. Neat is a synonym of Fair. Fair is a synonym of Pure. 
Touchdown --IsA--> Landing --AtLocation--> Airport 
Nightmare <--RelatedTo--> Street <--RelatedTo--> Neat <--Synonym--> Fair <--Synonym--> Pure 