The enormous Trajan's Column near the Quirinal Hill was built in the 2nd century AD to commemorate Emperor Trajan’s victories in war. The column itself is 98 feet tall, but standing on its pedestal the entire structure is 125 feet tall.
The column is decorated with the story of Trajan’s war triumphs told in pictures, spiralling around the outside of the column, with the story starting at the bottom. Trajan’s ashes were originally interred in the base of the column. Amazingly, the column itself is actually hollow and contains a spiral staircase that leads to a viewing platform on the very top.
Trajan's Column was originally topped with a statue of Trajan himself, but in the late 16th century the then-Pope Sixtus V ordered that a statue of Saint Peter be put atop the column. It’s the statue of Saint Peter that you still see today. In order to see all of the bas relief carvings, you’ll need to visit Rome’s Museum of Roman Civilization, which has plaster casts of them on display - all at eye level.