Western Eurasia covers most of Europe and is the westernmost section of the Palearctic realm with five major subrealms -- Greater European Forests, European Mountain Forests, Black Sea Forests & Steppe, the Mediterranean, and the British Isles -- and 13 bioregions in total as defined in the Bioregions 2020 framework. The Greater European Forests cover most of the European mainland with a group of EuropeanMountain Forests extending from Switzerland to the western edge of the Black Sea. To the east, the vast Pontic Steppe defines the Black Sea Forests & Steppe subrealm, which includes southern Russia and most of Turkey. In the south, three bioregions span the length of the Mediterranean – from Spain, Italy, and Greece to western Turkey, Lebanon, and Israel -- with a fourth surrounding the Azores islands off the west coast of the Iberian Peninsula. Lastly, the British Isles are defined as their own subrealm with a uniquely mild climate influenced by the Gulf Stream.