This 16.5 meters long dragon staircase slab at the Forbidden City in Beijing (fig.) is monolithic and said to weigh around 250 tonnes. It was brought in from outside Beijing and transported in winter by creating ice patches on land by pouring water on the freezing soil, resulting in an ice road over which it could then be slid. About 20,000 workers were involved in moving the slab along the track and in order to get a sufficient amount of water, a well was dug every 500 meters.