Trajan's Column.

113 AD

128 ft tall, made of 29 huge blocks of white Italian marble. On top was a 16 foot bronze statue of Trajan in military dress.  It is a victory monument and depicts two battles and victory over The Dacians. It has 2,600 figures carved into it.

There is a spiral staircase inside carved out of solid stone.

Now it has St. Peter on the top. 

http://en.wikipedia.org/wiki/Trajan%27s_Column