Castle Square, or Plac Zamkowy in Polish, is a historic square located in the heart of Warsaw, Poland. The square is dominated by the Royal Castle, which served as the official residence of Polish monarchs from the 16th century until the end of the 18th century.

The Castle Square is a popular tourist destination and one of the most recognizable landmarks in Warsaw. The square itself is surrounded by historic buildings and monuments, including the Royal Castle, the Sigismund's Column, and the colorful facades of the 18th century tenement houses. The column, which was erected in the 17th century, is a tribute to King Sigismund III Vasa, who moved the Polish capital from Krakow to Warsaw in the 16th century.

In addition to its historic significance, Castle Square is also a vibrant hub for cultural events and festivities. In the summer months, the square is filled with outdoor concerts, markets, and festivals. The Christmas market held on the square is particularly popular, featuring a large Christmas tree and traditional food and crafts.

Overall, Castle Square is a must-see attraction for anyone visiting Warsaw, offering a glimpse into the city's rich history and vibrant cultural scene.