Wiedersehen literally means "seeing again" or "reunion." It's a compound word that beautifully captures the sentiment of hoping to meet someone again.
In Nena's "Mondsong," the extraterrestrial narrators, who briefly visited Earth, express their hope for a Wiedersehen with humanity. They left their car on the moon and are inviting humans to come visit, making this word a key part of their friendly invitation and the song's unique narrative.
Imagine you're on the moon, looking down at Earth. That's the perspective of Nena's song "Mondsong" (Moon Song). The narrator, a moon-dweller, describes a quick visit from some "people from the Earth" who arrived suddenly and left just as fast. They were in such a hurry that they left something important behind: a car, with the keys still in the ignition!
This isn't just a song about a lost car, though. The moon-dwellers are inviting the humans to come back and pick it up, but they also have a message. From their vantage point, things on Earth look "pretty bad." They see what people are doing and worry that "nothing will be left." The song ends with a hopeful but urgent piece of advice for humanity: "Run towards the sun... good luck and don't waste any time."