Finding a long-term solution that doesn't degrade the natural and cultural ecosystems is what sustainable travel is all about. It is important that sustainable travel minimizes the negative effects of tourism and, if possible, helps the local community at large. The World Tourism Organization defines sustainable tourism as "development that serves the demands of existing visitors and host areas while safeguarding and expanding future opportunities." Environmental sustainability is expected to be achieved by balancing economic, social, and aesthetic requirements with the preservation of the environment's vital ecological processes, biodiversity, and life-support systems".