As a famous Slovak scientist, Harmatta conducted business in Spisske Podhradie. He established factory that produced spikes, chains and iron barrels and employed approximately 200 workers. He was instrumental in installation of an electric current in the town. Jan Harmatta was an author of many inventions dealing with welding and processing of semi-finished products. The most famous is resistance point spot-welding. He was granted a patent on his invention in the USA. This invention is still used when producing bodyworks of cars. There is his memorial room in Spisske Podhradie. It is possible to enter Jan Harmatta´s room with the TIC employee.