Brno is an important urban conservation area, and the second largest city of the Czech Republic. The settlement of population, in the city of Brno, dates from the arrival of the Slavs in the sixth century, through the Great Moravian Empire to the present day. Since the end of the thirteenth century, the city has been protected by the Špilberk Castle, which, over time, became a margrave residence of the Luxembourg family. The metropolis acquired, in this way, the category of the capital of Moravia. In the same way, as other cities, Brno also has its hidden secrets, for example, the tunnels. For tourists from around the world, the biggest point of attraction, in the town, is the residence Tugendhat. This is the most important European building designed by the architect Ludwig Mies van der Rohe. The house was inscribed, in 2001, on the list of UNESCO World Heritage.