Oh, isn't it Narva Castle? Narva Castle is great and worth visiting. "The castle, which is also known as Hermann Castle, was built in the 13th century but the Danes as a residence for the Danish King’s vice-Regent. Inside the castle is the Narva Museum as well as a collection of handicrafts workshops where you can watch and even learn the skills used in medieval times. The castle tower overlooks the Ivangorod castle on the Russian side of the river." (source: www.confiduss.com/en/jurisdictions/estonia/geography/ )
