“Niedersachsen” is a state in Germany. If you like hiking and nature you might like to do this:
Brunnen- und Quellenwanderung in Wolfsburg ( capitol of Volkswagen 
)
…or discover the near regions by bike:
If you prefer the city. Berlin is only 1h by ICE ( express train )
@nefliegchen and @janu94 this might be of interest to you 