One of the reasons the Romans first colonized the area immediately to the west of the River Danube and established their regional capital at Aquincum (now part of Óbuda, in northern Budapest) is so that they could utilize and enjoy the thermal springs. There are still ruins visible today of the enormous baths that were built during that period. The new baths that were constructed during the Turkish period (1541–1686) served both bathing and medicinal purposes, and some of these are still in use to this day. Budapest gained its reputation as a city of spas in the 1920s, following the first realization of the economic potential of the thermal waters in drawing in visitors. Indeed, in 1934 Budapest was officially ranked as a “City of Spas”. Construction of the Király Baths started in 1565, and most of the present-day building dates from the Turkish period, including most notably the fine cupola-topped pool.