The end of the 20th century and the first decades of the 21st century, have been characterised by the intensive growth of cities and the tourist industry, and by the ever-growing awareness of development-related challenges, facing the whole human race. Large cities are at the heart of these major phenomena. Their populations are constantly growing; they are places where business, cultural, and scientific activities, are located. They also attract an ever-growing number of tourists. The fact that so many functions co-exist within the limited space of these cities, is both a chance for development.