1. Piazza Castello is the main square in Turin, Italy, and is considered the heart of the city. It is surrounded by several important buildings and landmarks, including the Royal Palace of Turin, Palazzo Madama, and the Baroque facade of the Turin Cathedral. The square is named after the castle that once stood in the area, which was demolished in 1869. Piazza Castello is a popular gathering place for locals and tourists, and often hosts cultural events, markets, and concerts.

Interesting facts about Piazza Castello include:

- The square has been the site of several historical events, including the announcement of the unification of Italy in 1861.

- Piazza Castello was once the site of a Roman theater, which was uncovered during excavations in the late 19th century.

- The square is known for its impressive architecture, with buildings reflecting a variety of styles, including Roman, Baroque, and Neoclassical.

2. Piazza Castello is an open public space and is accessible at all times. There are no specific working hours or entrance fees. However, the individual buildings and landmarks surrounding the square may have their own opening hours and admission fees. It is recommended to check with each attraction for their specific information.

3. Piazza Castello is located in the center of Turin, making it easily accessible by public transportation. The square is served by several bus lines and is within walking distance of several tram stops. The closest metro station is the Porta Nuova station. It is also possible to reach Piazza Castello by car, but parking may be limited in the area.