Trier's cathedral is the oldest church in Germany, and the walls prove it. At its heart stand the bricks of a Roman building, a great hall from the early fourth century, which Constantine's mother, Helena, is said to have given to the Christian community. Around that core, bishops and archbishops added, rebuilt and altered over sixteen centuries, so that the cathedral today is a patchwork of Romanesque towers, a Gothic cloister, baroque chapels and a Roman brick outer wall in places. From outside the mix looks puzzling, and from inside it is magnificent.
The cathedral's great treasure is the Holy Robe, the garment said to have been worn by Christ at his crucifixion, which is kept in a case and shown to the public only on rare occasions, drawing large crowds of pilgrims. Whatever one thinks of the relic, the tradition behind it is old, and the cathedral has been a place of pilgrimage for centuries. The archbishops of Trier were also prince-electors of the Holy Roman Empire, which means they helped choose the emperor, and their tombs fill the aisles.
The Liebfrauenkirche, the neighbouring Gothic church, shares the UNESCO listing, and the two buildings stand together. The cathedral treasury and museum hold gold, ivory and manuscripts, but opening hours vary and are worth checking.
The old city centre is largely pedestrianised, so find a place for the bike on the edge and walk the short distance. Fuel, food and coffee are easy in Trier, which has a hundred thousand people and the usual array of supermarkets and bakeries. The Moselle riverbank is a pleasant place to walk and the old Roman bridge, which still carries traffic on its Roman piers, crosses the river a few minutes away.
For riding, take a day to follow the Moselle upstream or downstream, or climb into the Eifel, where winding roads cross wide plateaus and drop into wooded valleys. Fog can fill the valleys in autumn and winter. Spring and summer are best, though weekends bring more traffic. Local bakeries sell rich cakes and pretzels, and a late afternoon coffee in the cloister garden of a nearby café is a good break.