"Within the irregular arc of coral the lagoon was still as a mountain lake-blue of all shades and shadowy green and purple."
Creative Commons AttributionLagoon - Credit: Nils Rinaldi
Lagoons  are shallow coastal bodies of water, often separated from the ocean by a barrier reef parallel to the shoreline. Inlets, either natural or manmade, cut through the barrier reef and permit tidal currents to transport water in and out of the lagoon.