Spas (banja in Serbian) with their numerous geothermal springs, along with countless air spas, that have beneficial effect on the general health, present a great natural wealth of Serbia. The whole concept of tourism in Serbia was established in the most visited spa in Serbia – Vrnjačka Banja. Nature was generous to Serbia in the form of more than 1,000 geothermal and mineral waters in 40 Serbian spas. There is still a centuries-old tradition of using thermal springs, just as they were used 2,000 years ago by Romans for relaxation and healing of their legionnaires. It is believed that Romans used the thermo-mineral waters in Gamzigrad spa, because they built the imperial complex Felix Romulianu in the vicinity of it.