Wall can be used for Separation. Separation is related to Continent. Continent is related to Coast. 
Journey is a different concept from Walk. Walk is a type of Accompany. Accompany is a type of Travel. 
Wall --UsedFor--> Separation <--RelatedTo--> Continent <--RelatedTo--> Coast 
Journey <--DistinctFrom--> Walk --IsA--> Accompany --IsA--> Travel 