Tourism and Development Sustainable tourism is a way of tourism which pledges to sustainable principles. These principles make compatible the tourist activity development with respect and preservation of natural, cultural and social resources, which eases tensions among tourism industry, visitors, native communities and environment. The concept of sustainability first appeared in 1991 defined as “a characteristic of a process or state that can be maintained indefinitely”, but the most accepted definition of the concept of sustainable development is the one proposed by the report Our Common Future (also known as the Brundtland Report), released by the United Nations World Commission on Environment and Development: "Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs." This definition includes two key elements: the human needs and the limitations of the global ecosystem. The concept of sustainable development does not include any guidelines for an ideal relationship between the human society and the nature; instead, this is a flexible concept that can be adapted to different ethic behaviors and management strategies. In the 1991 World Conservation Strategy, Caring for the Earth, its meaning is “improving the quality of human life while living within the carrying capacity of supporting ecosystems.” The need for a sustainable development is a global priority pointed out in the plan Agenda 21, adopted in the UN Conference on Environment and Development held in Rio de Janeiro in 1992, also known as the Earth Summit, and in the Fifth European Community environment programme: towards sustainability. Sustainable development is determined by three main aspects: 1. Environmental sustainability, which must ensure the compatibility of development with essential ecological processes, resources diversity and biological diversity. 2. Economic sustainability, which must ensure the economic efficiency of development, which must benefit all the stakeholders of a tourist destination or region, and a local management of resources. 3. Social sustainability, which must ensure the participation of every stakeholder involved in the decision-making processes. The UNWTO (United Nations World Tourism Organization<) definition of sustainable tourism is based on the definition of sustainable development stablished in the Brundtland Report: “Tourism that takes full account of its current and future economic, social and environmental impacts, addressing the needs of visitors, the industry, the environment and host communities.” This theoretical definition determines a tourism development strategy that pursues a balance among the economic, sociocultural and environmental impacts of the tourist activity.