1. Giola, Thassos (Greece)

A lagoon is defined as a shallow body of water that is separated from the larger body of water it is drawn from by a shoal, barrier reef, or something of that kind. In the image above you can see a lagoon protected by a rock barrier, for example.
2. Four Seasons Hotel, Bora Bora (French Polynesia)

Typically covered with glorious turquoise waters as here in Bora Bora, there are actually two generic types of lagoons: atoll and coastal.