Citation Hunt

The Wikipedia snippet below is not backed by a reliable source. Can you find one?

Click I got this! to go to Wikipedia and fix the snippet, or Next! to see another one. Good luck!

In page Cologne Cathedral:

This text has been unreferenced on Wikipedia for a very long time. If you can't find a source, be bold and remove it!

"

Work resumed in 1842 to the original design of the surviving medieval plans and drawings, but using more modern construction techniques, including iron roof girders. The nave was completed and the towers were added. The bells were installed in the 1870s. The largest bell is St. Petersglocke.[citation needed]