You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Bern

Context:
Bern is built on very uneven ground. There is an elevation difference of several metres between the inner city districts on the Aare (Matte, Marzili) and the higher ones (Kirchenfeld, Länggasse).

Question:
What type of ground was Bern built on?

uneven ground.