Going through the article I have understood that it is the distance between two cities.

通过这篇文章我已经明白这是两个城市之间的距离。

youdao

What I failed to appreciate was the distance between the two cities.

我没有意识到这两座城市间的距离。

《牛津词典》

You probably know that Seattle and Raleigh are on opposite sides of the United States, but a map helps you visualize the distance between the two cities.

您可能知道西雅图和罗利是在美国的两端，但地图能够帮助您显示出两个城市之间的距离。

youdao

Music has no interest in borders, but the reality of the conflict meant that distance developed between Ireland's two great cities.

BBC: London 2012: Orchestras share stage for historic concert