the basis of an underwater metropolis

Massive coral reefs begin with tiny coral larvae,which settle on the seafloor hard surfaces and metamorphasize into coral polyps.Over time, these polyps generate rock-like skeletons made of calcium carbonate.Together, colonies of polyps produce large three-dimensional structures,which form the basis of an underwater metropolis.These coral complexes are full of nooks and crannies that house and protect countless life forms.