RL617 controls the height of buildings in Canberra’s inner suburbs, but it’s not the name of a shadowy secret society. It actually refers to the height of the base of the flag pole at Parliament House. It’s also one of Canberra’s more ridiculous planning rules.
Under the rule, buildings in the City Centre, the Inner North and Inner South cannot be higher than 617 metres above sea level. Now, it really depends on the natural ground level of the block of land, but you generally won’t see any buildings in these areas above 12 to 15 storeys.