Clara Barton made key contributions to the field of nursing and humanitarian work, notably as the founder of the American Red Cross. During the Civil War, her dedication to caring for wounded soldiers earned her the nickname "Angel of the Battlefield." Barton advocated for disaster relief and organized the first aid service during international conflicts. Her tireless efforts to establish a formalized approach to emergency care and relief laid the groundwork for modern nursing practices and humanitarian organizations, significantly transforming how society responds to crises.