In the last few decades a new branch of tourism emerged making its way between the tourism industry: Responsible Tourism. It operates according to the principles of social and economic justice and in full respect of the environment and cultures, puts at the center the local host community and its right to be the key player in the sustainable and socially responsible tourism development of its membership territory. Therefore, the main purpose that this alternative typology of tourism is determined to accomplish is encouraging positive interactions between the triangle: tourism industry, local communities, and the travelers. All the three parts have to be aware of the possible effects of their actions towards the local populations and the environment. Mass Tourism, in these perspectives, needs a specific historical digression. It could be considered a double-edged sword, as it gave the opportunity to the majority of the people to travel and reach remote destinations using different means of transport but, at the same time, it established, among other things, a standardization process, creation of stereotypes, an authenticity drop, pollution, accumulation of rubbish… Before its advent, only aristocratic classes had the privilege to travel for leisure motivations, for work and, finally, to experience a gap year far from home, an opportunity to grow. Mass Tourism practice, over time, has provoked permanent damages, ravaging the environment and bringing discomfort to local communities or even the escape of residents. Here, another analogous touristic dynamic comes into force: Overtourism, that is touristic overcrowding of a holiday destination. When talking about natural touristic destinations, such as reserves, oasis, beaches, parks and mountains, it is of fundamental importance that tourism respects the environment, including flora, fauna and microclimate. Instead, when the destination is a city, tourism has to mainly respect residents, as well as the local culture and archaeological sites, substantial microcosms that need to be protected. If this does not happen, it means that overtourism or unsustainable tourism for the place, for nature, for the people who live there is occurring. “Fortunately”, few touristic destinations in the world suffer from an excessive presence of tourists. There are various causes that come into play: from famous movies that make renowned specific places, to the ease it is possible to reach any world corner, to cruises that, having reduced costs, attract great presences of travelers around the seas. Another important factors that have to be mentioned are the role of social media, influencers, TV programs and movies in promoting potential destinations and the low-cost airlines, with their huge carbon footprints.