Stattreisen e.V.

This non-profit organization offers excellent tours of Cologne, led by volunteers. The prices are moderate and there is a huge list of tours, including (besides the more regular tours) Koelsch tours (for testing the breweries) or language lessons in the local dialect (again, in a brewery). Ask for English tours, some guides are willing to conduct a normally German tour in English.

Website

stattreisen-koeln.de (opens in a new tab)