The Balaton LTSER Platform is dedicated to the study of the largest shallow lake in Eastern Europe, situated in the mid-western part of Hungary. The site, which is a popular holiday resort, consists of the lake and its watershed. Lake Balaton went through considerable changes in trophic state during the past decades. After a period of anthropogenic eutrophication from the late 1960s until the mid '90s, restoration measures aimed at reducing the nutrient load reaching the lake led to gradual reoligotrophication. The Balaton Limnological Research Institute, situated on the Tihany peninsula, had an important role in improving the water quality and the ecological status of the lake by providing sound scientific knowledge for the decision-makers and the general public.