It is not widely known that one of the earliest AC (alternating current) electric power systems in the world has been built up in Croatia, on the beautiful Krka waterfalls (one of Croatian national parks). It brought light to the city of Sibenik, 11 km from the power plant. It was built in 1895, one year before Nikola Tesla‘s famous power plant on the Niagara falls. The chief engineer was Ante Supuk. The plant brought light to the Šibenik cathedral, which was the first cathedral in the world lighted with AC. At the time when Krka – Šibenik AC electric power system was built, there was no transmission system for larger distance. Krka-Šibenik was one of first integrated power systems. It was a two-phase system in time when major cities like London and Rome had one-phase systems. With time, other cities also adopted multiphase (or polyphase) systems invented by Nikola Tesla, and this is kept up until today. This was one of the first commercial power systems, supplying an entire city with multiphase electric power. For more information, see Milestones: Krka-Šibenik Electric Power System, 1895.