1948–1989 · reservoir built 1961–1965 The factories and the inland seaTovárne a vnútrozemské more

After the war the lowland was industrialised deliberately. Drainage schemes turned marsh into some of the best arable land in the country, factories and a pipeline construction boom in the 1960s pulled workers off the farms, and blocks of flats went up around a market town that had held only a few thousand people. The single largest change was Zemplínska šírava, built between 1961 and 1965 to hold floodwater and irrigate the plain — 33 square kilometres of water under the Vihorlat, on ground where no village had stood. Holidaymakers were an afterthought: by 1968 half a million people a year were coming, and seven resorts were built along the northern shore in the 1970s and 1980s.Po vojne nížinu zámerne industrializovali. Odvodňovacie projekty premenili močiare na jednu z najúrodnejších oblastí krajiny, továrne a stavebný ruch okolo ropovodu v 60. rokoch odviedli ľudí z polí a okolo trhového mesta s pár tisíckami obyvateľov vyrástli sídliská. Najväčšou zmenou bola Zemplínska šírava, postavená v rokoch 1961 – 1965, aby zadržiavala povodňovú vodu a zavlažovala rovinu — 33 štvorcových kilometrov vody pod Vihorlatom, na mieste, kde predtým nestála nijaká obec. Rekreácia bola až dodatočným nápadom: už roku 1968 sem prišlo pol milióna ľudí a v 70. a 80. rokoch postavili pozdĺž severného brehu sedem stredísk.