1856-1920 1866-1955 1873-1933 1874-1922 20thcentury adventurers autobiography biography britishantarcticexpedition(1907-1909) descriptionandtravel discoveryandexploration ernesthenry explorers henson history k2(mountain) luigiamedeodi matthewalexander modern mountaineeringexpeditions pakistan peary polarregions shackleton