This little ceramic castle afloat on its own island in the bay off Praça XV looks like the dwelling of a fair elfin princess, but in fact was built as the headquarters for the Brazilian Custom Service. Initial plans for a rather prosaic edifice were shelved after Emperor Pedro II intervened, and the result was the tiny jewel box of a building, designed by Adolpho Del-Vecchio. On the inside, alas, this Gothic Revival palace is mostly a small and rather boring museum on the Brazilian navy, which owns the island. The tour lasts about 2 1/2 hours. On weekdays, the trip to the island is by boat, whereas on weekends it's by bus along a causeway.