The size of a city grows with the number of people coming to live, work or just spend time in that region. On the other hand, two cities with the same population growth, may not expand in area the same way due to the policy of growth in height. This relation area/height  is very important for the day to day life in a city. From the point of view of tourism, If the city is too big and the points of tourist interest are too far apart, tourists lose a lot of time in transport and if the city is too small it turns out not to justify the short holidays because it spends more time on the trip than to visit. Large metropolitan areas are a nightmare for tourists because, as we know, all cities have important places of interest outside the historic center and if the access to these places is very time consuming, tourists do not visit them. In the case of Lisbon we find a perfect stopover for tourism because you can reach the places of great interest, such as Sintra, Alentejo or the beaches in a few minutes.