The Ibiza, Biodiversity and Culture site in Spain was inscribed on the World Heritage List in 1999. The site's dense prairies of Posidonia oceanica, an important (and highly productive) endemic sea grass, provide coastal protection from storms, food and habitat for a broad diversity of marine life, and critical nursery grounds for fishery species. Among the site's other significant marine values are underwater caves that offer access to important geological features, the most diverse pillow coral community (Cladocora caespitosa) in the Mediterranean, and a valuable population of Ecteinascidia turbinata, a tunicate or "sea squirt" with recognized use in preventing and treating cancer. Ibiza also offers protection to three globally endangered species, including the Mediterranean monk seal (Monachus monachus).

Today, over 40 World Heritage sites are listed for their marine values. Together, they can be considered the "Crown Jewels of our Ocean" and are recognized for their outstanding beauty, exceptional biodiversity, or unique ecological, biological, or geological processes. Learn more about this and other marine World Heritage sites.