What nature-friendly ideas started a new branch in the tourism business?

A new branch of tourism is ecotourism. It involves visiting relatively untouched places in remote areas. Ecotourism is often misinterpreted as any form of tourism involving wildlife - but it's completely different from jungle tourism or safari. Eco-tourists are against disturbing the environment; even taking photos is not recommended. Take only memories and leave only footprints is a very popular slogan for them.