In total, this would raise the length of the system by 6.5 kilometres and make it the most important transport artery.
The city then measured 19 by 13 kilometres (12 by 8 mi), with a population of nearly a million people.
The change was slight, but it would increase her perihelion distance by ten million kilometres.
Within a few years, people pushed the Heide back out of the city centre by two kilometres.
The southern city walls were moved south by 0.8 kilometres, to allow more space for the future Imperial city complex.
In other locations the new road deviates from the original by many kilometres.
Perihelion also changed, increasing by 50 million kilometres, rendering the comet far less visible from Earth.
In a region of around 30 by 6-10 kilometres there are today around 1600 abris.
The island had shrunk by around 500 square kilometres in the last twenty years.
The plains encompass an area of 700,000 km2 (270,000 mile2) and vary in width through their length by several hundred kilometres.