Antarctica is a land of extremes: it is the coldest and driest continent on Earth and has the highest average elevation of any continent. The landscape remains mostly untouched by humans, with only a handful of scientific bases and a "permanent" population of scientists numbering only a few thousand. Visitors to Antarctica generally must brave rough sea crossings aboard ice-strengthened vessels, but those who do are rewarded with amazing scenery and tremendous wildlife. Visitors to Antarctica often speak of its pristine beauty and serenity. Animal lovers, birdwatchers and photographers are also in for a treat in Antarctica with its various species of penguins, seals and birds that are native to the frozen continent.