SMS Leitha or Lajta Monitor Museumship was the first river monitor in Europe and the oldest and also the only remaining, fully restored warship of the Austro-Hungarian Navy. Currently it is moored on the Danube in Budapest near the Hungarian Parliament Building as a museum ship.
The monitor was an innovation in the history of warship construction. The first European river monitors were constructed by the Austro-Hungarian Monarchy, namely the SMS Leitha and SMS Maros, and since then the river warships of the Monarchy were built in pairs. According to the customs of that time, river warships were named after the rivers of the Austro-Hungarian Empire. The names were chosen to reflect the dual nature of the monarchy; thus, one of the ships received an Austrian name, the other one a Hungarian. This is the reason why this warship was named after the Austrian river Leitha, while her sister ship was named after a Hungarian river, the Maros.
Wikipedia https://en.wikipedia.org/wiki/SMS_Leitha
Official Website https://en.wikipedia.org/wiki/SMS_Leitha
Coordinates 47°30'31.371" N 19°2'41.475" E