This pillar was built in memory of the National Congres that devised our Constitution. It has a height of 47 meter and was built between 1850 and 1857 with as an architect Jozef Poelaert.
At the four corners you can see statues depicting important principles: freedom of education, freedom of religion, freedom of union and freedom of the press. On the top you can see a statue of King Leopold I. Underneath is situated the Grave of the Unknown Soldier (from 1922) (War Monument).
Translated based on Alan Loobuyck:
'There is also the eternal flame, that is burning always. There is permanently a guard, in order to avoid that vandals, like they try from time to time, succeed in putting out the fire. Every year on October 11th, the unknown soldier and every victim of armed conflicts (incl terror victims) are commemorated.'