The majority of Antarctica is covered in a permanent ice cap almost 5 km thick in some places. However, Antarctica was not always a barren and frozen land. The discovery of fossil plants, reptiles, and marsupials of the same species as those found in other parts of the Southern Hemisphere indicates that Antarctica was once joined to the other continents and that its climate was once temperate. The Antarctic Peninsula, or Marielandia, currently has the mildest climate on the continent. It is here that Antarctica’s only two vascular plants grow, and it is here that wildlife such as penguins, flying seabirds, and seals are most plentiful. In addition to global climate change and the depletion of ozone over the south polar region, growing tourism to the peninsula may become a serious concern. Plants and animals of this region are highly adapted to the extreme and inhospitable environment, and thus, can be vulnerable to the slightest disturbance.