Standing at the confluence of the Nemunas and the Neris, the castle was built in the 14th century to repel attacks by the Teutonic Knights. It is not only the oldest brick castle in Lithuania but also the only one with two rows of defensive walls. A settlement grew up around this Gothic fortification and developed into today's city. The castle – where, according to legend, Queen Bona Sforza's army mysteriously sank underground – was first mentioned in written sources as early as 1361. Rebuilt several times, the castle lost its importance in 1408, when Kaunas was granted Magdeburg rights and the city's life moved to what was then Market (Town Hall) Square. In the 16th century the castle housed a prison, and the souls of those once imprisoned there, still not at rest, are said to haunt Kaunas Castle at night. Today the castle houses a branch of the Kaunas City Museum, and the city's cultural events are held around it every year. Next to Kaunas Castle lies Santaka Park, known as the heart of Kaunas. Walking through the park you can see the Nemunas and the Neris merge, and there are plenty of sights: a sacrificial altar where pagan rites were performed; Pope's Hill, where Pope John Paul II visited and celebrated Holy Mass in 1993, and Pope Francis in 2018; a statue of Pope John Paul II; and St George's Church with the Bernardine monastery ensemble. In 2018 a sculpture of Vytis, “Freedom Warrior”, was unveiled next to the castle; it was created by the sculptor Arūnas Sakalauskas and the artists Borisas Krylovas and Olesius Sidorukas from Ukraine.