Featuring a very complex eruptive history, Terceira is different from the other islands thanks to the variety of volcanic remnants that exhibit quite unique shapes. The island hosts 7 geosites with remarkable geodiversity: Algar do Carvão [pit cave], Caldeira de Guilherme Moniz [volcanic crater], Caldeira da Serra de Santa Bárbara and Mistérios Negros [volcanic crater], Furnas do Enxofre [fumarole field], Monte Brasil [hill], Pico Alto [peak], Biscoito Rachado and Biscoito da Ferraria [forest reserve], Ponta da Serreta [headland] and old lava flows.
The Terceira Nature Park, the largest of the Azores Archipelago, includes 20 protected areas spread throughout the island and the sea off its coast. There are quite a few areas of natural vegetation that have witnessed little to no human intervention, such as
the volcanic crater Caldeira da Serra de Santa Bárbara, which is listed as a Strict Nature Reserve of the Terceira Nature Park and features a wide variety of endemic fauna and flora.
In the middle of the Atlantic, about halfway between America and Europe, this verdant island is visited by birds from both continents that deviate from their routes. Some species from America and Europe grow side by side, while others that geography had separated thousands of years ago get reunited and a few that are extinct in continents emerge on the island. The coastline and the islets off the coast are important habitats for some of Europe’s most important species of seabirds that visit the Azores every year to nest or simply to rest.