Dellbrücker Heide is a nature reserve with a small gravel pit lake. It is one of the most ecologically valuable areas in the Rhineland. Species you can spot include butterflies and grasshoppers that have otherwise gone extinct in other areas of the Bergische Heideterrasse, even in Wahner Heide. You can also spot a number of other open-habitat species such as the natterjack toad and the red-backed shrike. To maintain this habitat open – and thus preserve the associated species – there is a shepherd with goats and sheep. The nature reserve organizes free tours that you can join.
Next to Dellbrücker Heide is a larger quarry lake: the Höhenfelder See. It is not a nature reserve and is used for recreational purposes such as barbecuing, sunbathing, or running. A bit further north, in Köln Dünnwald, there is a wildlife park, an arboretum, and an outdoor bath (named “Waldbad Dünnwald”). I particularly enjoy this whole area during Spring, when the brooms and rhododendrons are in flowers, and when you can already spot the sand lizards sunbathing.
Dellbrücker Heide is an 11-minute walk from the Cologne Dellbrück train station, which is 14 minutes by train from Cologne Central Station (S11).