Venice, Italy, has a San Marco Square, also known as Venice Central Square. It is the public activity center of Venice's political, religious and traditional festivals. The square is surrounded by the Duke's House, St. Mark's Cathedral, the quadrangular bell tower, the St. Mark's Library and other buildings. According to the geophone guide, Venice has been in a period of ground decline in recent years, and its groundwater level has been much higher. The original drainage system has been basically ineffective, a little rain in St. Mark's Square will accumulate water, so the square has a springboard for tourists to pass through.