en.Wikipedia wrote:The structure is about 30 metres (98 ft) in height, 35 metres (125 ft) including its large pedestal. The shaft is made from a series of 20 colossal Carrara marble drums, each weighing about 32 tons, with a diameter of 3.7 metres (11 ft). The 190-metre (625 ft) frieze winds around the shaft 23 times. Inside the shaft, a spiral staircase of 185 stairs provides access to a viewing platform at the top. The capital block of Trajan's Column weighs 53.3 tons, which had to be lifted to a height of c. 34 m.
The carvings are crowded with sailors, soldiers, statesmen and priests, showing about 2,500 figures in all.