Invisible treasure.
Dream dictionary: Cupola dream meanings
(See Watchtower)
…(Cupola | Minaret | Observatory) In a dream, a watchtower repre- sents a notable person. Seeing a watchtower from a distance in a dream means victory over one’s adversary, attainment of one’s goals, rising in rank, or it could mean happiness. If a merchant sees a watchtower in a dream, it means prosperity, presiding over his fellow merchants and gaining power. Building a watchtower in a dream has the same interpretation as building an edifice or a house….