**2.3. Urban tourism and sustainability**

Urban tourism has been present since the beginnings of Mesopotamia and Sumer. Old Romans travelled to Greek cities, especially to Alexandria and Athens. Cities were then the centres of music, art, literature, architecture and places of encounter of different cultures. In the Middle Ages, long trips were recorded when young aristocrats visited several European cities [20].

The most significant tourist trips to cities date back to the end of the nineteenth century. At the end of the 1970s, tourism has become an increasingly important part of the economy of European cities. Trends, statistical indicators of the number of overnight stays, tourist consumption and total tourist traffic in the first decade of the twenty-first century show that the share of urban tourism in the overall European economy is becoming more and more significant [21].

Urban tourism and its definitions are based on the city as a complex social and economic system as well as the city as the destination with many tourist attractions and valuable resources. The national conference on urban tourism (Rennes, 1988) concluded that urban tourism is a set of tourist resources or activities located in towns and cities and offered to visitors from elsewhere [22].

Many researchers attempted to define the term urban tourism, as Ashwoth [23], Law [24], Howie [25].

Considering the definitions of the aforementioned authors, it is possible to state that urban tourism is a multi-layered complex of activities arising as a consequence of many resource attractions in a town or a city.

Urban tourism has been developed especially in cities with open urban spaces, landscaped parks, unique urban and architectural design solutions, attractive material and intangible cultural heritage, efficient traffic solution, well-known universities and scientific research centres, concentration of well-equipped shops and shopping centres, restaurants with quality gastronomic offer and dynamic street life. Furthermore, urban tourism is well developed in cities that are the base of tourists who have recognised the entire region as a worthwhile tour destination. Some authors point out the attraction of the city as a tourist destination [26] or specific elements of urban tourism products, i.e. city tourism resources that determine the city's attractiveness to its visitors [27].

The contents of the attractions are divided into three main groups: **I. ambience attractions** (climate, landscape, culture and hospitality); **II. material attractions** (cultural and historical heritage, architecture, city squares, streets, parks, fairs, exhibitions, business-congress centres, sanctuaries and sacred objects, etc.); **III. happenings** (permanent attractions, business, sports, religious, political gatherings and events, local festivals; events of special local and regional significance, etc.).
