staten island
The Blue Lagoon
I believe it is called goo lagoon
a lagoon
An atoll is an island that encircles a lagoon. The floating cities in the film are like that.
A circular coral island that encloses a lagoon is called an atoll. Atolls are typically formed from coral reefs that grow around the rim of a submerged volcanic island.
Each island is surrounded by a reef enclosing a shallow lagoon.
staten island
An encircling coral reef or sandbar can create a shallower area of water near an island, called a lagoon.
An island with a central lagoon is called an atoll. Kwajalein in the Indian Ocean is a very good example.
A Barrier Reef. The barrier reefs grow parallel to the shore of an island and are separated from it by a deep lagoon.
An atoll is a ring-shaped coral island or string of islands that surround a lagoon. Atolls typically form from volcanic islands that sink into the ocean, leaving a coral reef formation around the edge of the submerged island. The lagoon in the center of an atoll is often shallow and can support diverse marine life.
Poveglia Island is located in the lagoon of Venice, Italy.
barrier reef
If you are referring to the crossword puzzle hint, try Atoll.
it's an island with a water court-yard
atoll