9:00 — Kölner Dom
Start before the crowds at Cologne Cathedral, a UNESCO World Heritage site and one of the largest Gothic churches ever built — begun in 1248 and not finished until 1880. Inside, the golden Shrine of the Three Kings sits behind the altar. Entry to the church itself is free; go early for quiet.
10:30 — Climb the south tower
Roughly 530 spiral steps lead to a viewing platform about 100 meters up. It is a workout, and the Rhine panorama is the reward. Skip it if stairs are an issue — the riverbank views come later.
12:30 — First Kölsch and lunch
Steps from the cathedral, the traditional brewhouses pour Kölsch, the city's pale beer, served in slim 0.2-liter glasses that the roving waiters — the Köbes — replace automatically until you put a coaster on top. Früh am Dom is the classic first stop; order Himmel un Ääd, the local dish of black pudding with mashed potato and apple.
15:00 — Museum Ludwig
Beside the cathedral, this is one of Europe's best modern art museums, with a major Picasso collection and heavyweight Pop Art. Give it two hours.
18:00 — Hohenzollern Bridge at golden hour
Walk the pedestrian lane of the railway bridge, its fences heavy with thousands of love locks, then cross to the right bank for the postcard: cathedral, bridge, and river in one frame.
20:00 — Dinner in the Altstadt
Return to the old town's lanes for a brewhouse dinner — pork knuckle, sauerbraten, more Kölsch. Lively, communal, unfussy.