Hévíz is the most famous of Hungary’s spa towns, and rightly so, for it is home to Gyógy-tó, Europe’s largest thermal lake. It could be argued that Hévíz is the slowest town in the country, partly because the average visitor age is well over 60, but mostly because it’s impossible to move quickly after a dip in the lake’s therapeutic waters. A soak into this water-lily-laden lake is essential for anyone visiting the Lake Balaton region.