The Kottenforst is a big, flat, rather mysterious forest on the plateau south-west of Bonn, crossed by long, dead-straight avenues laid out by the Electors of Cologne in the eighteenth century as hunting rides. The Bellerbuschallee is one of them, and walking or riding along it you pass oak and beech, wet hollows and the occasional deer. Under the trees, though, lie traces much older than the Electors: the low ramparts of Roman practice camps, where legionaries from Bonn learned to dig defences quickly. These camps form part of the Lower German Limes World Heritage listing inscribed in 2021.
Bonna, on the Rhine below, was a full legionary fortress, and the river itself was the frontier here. The Romans also built one of their greatest engineering works nearby: the Eifel aqueduct, which carried spring water over ninety kilometres to Cologne, and fragments of it, with their thick crusts of limestone sinter, turn up across the region. On the far side of the Rhine rise the volcanic cones of the Siebengebirge, with the ruined castle of the Drachenfels on top, where legend says Siegfried killed the dragon and bathed in its blood.
Inside the forest itself the avenues are for walkers, cyclists and horses, not engines, so treat this as a place to park and wander. The riding is all around it. South through Wachtberg the lanes roll over open farmland with views to the Siebengebirge, and from there the Ahr valley, with its steep vineyards and twisting road through Altenahr, is half an hour away, as are the volcanic lakes and curving roads of the Eifel. Across the river, the climbs in the Siebengebirge are short but tight. Weekends bring plenty of fellow riders and some local speed controls.
Wachtberg, four kilometres away, covers fuel and basic shopping, and Bonn has every service you could ask for. In town, Beethoven's birthplace on the Bonngasse is a fine detour, and the beer gardens along the Rhine promenade are a good place to watch barges go by. In the forest, carry water, keep to the paths in the protected areas, and listen for woodpeckers drumming in spring.