Sustainable tourism aims to achieve a balance between the needs of tourists, the environment, local people, and businesses - a situation complicated by the numerous ethical issues at play. This paper presents an original account of the ethics of Aldo Leopold (1887-1948), a key figure in the development of modern environmental ethics, as it unfolds in his classic work, A Sand County Almanac. We argue that prior interpretations failed to incorporate Leopold's lynchpin cultural harvest idea into his larger "land ethic", and that a proper understanding of the cultural harvest reveals how tourism and other recreational activities can drive a person's ethical development. Ultimately, the land ethic helps us protect and nurture the most precious sustainability resource: human beings that value and respect the environment. The paper will be of value to tourism scholars, to heritage interpreters, to travel journalists, to tourism marketing staff, and to tourism managers. It shows the enormous opportunities for better marketing and heritage interpretation, notes the potential value of slow tourism, and the need for opening five key areas of the cultural harvest for tourists: storytelling, learning and knowledge, beauty and aesthetic appreciation, rarity and the hunt for trophy, and signature/personality.