During the Heroic Age, the Antarctic region became the focus of international efforts that resulted in intensive scientific and geographical exploration by 17 major Antarctic expeditions launched from ten countries. The common factor in these expeditions was the limited nature of the resources available to them before advances in transport and communication technologies revolutionized the work of exploration. Each of these expeditions therefore became a feat of endurance that tested, and sometimes exceeded, the physical and mental limits of its personnel. The "heroic" label, bestowed later, recognized the adversities which had to be overcome by these pioneers, some of whom did not survive the experience: a total of 19 expedition members died during this period.