Haapsalu Castle is an architectural gem built in the 13th century that was the seat of power of the local authorities until the end of the 17th century. It is one of the best-preserved castles in Estonia and home to the most famous ghost in Estonia – the White Lady! There is a museum on medieval history in the main castle, through which you can also access the southern cathedral, first mentioned in writing in 1279. There is a children’s playground inspired by the Middle Ages in the moat. You can visit the courtyard for free, but you have to buy a ticket to get to the museum.