La cathédrale Saint Lambert

Talking of heritage, this would have been the most important heritage site of Liège, if it was still standing:

St Lambert's cathedral was one of the biggest cathedrals in Europe and helped elevate Liège to the status of the 'Athens of the North', an important theological and philosophical centre (Edinburgh is also called the Athens of the North due to its many Greek neo-classical style 18th century buildings). The city became a hive of collegiate churches, ruled by bishop princes. After the French revolution and the nearly simultaneous Révolution Liégeoise, the cathedral became the symbol of the tyranny of the old order. In 1794, it was decided to demolish this symbol and to use the resulting rubble to divert the river and to improve the city. Here is the cathedral during the demolition process:

Finally, here is a model of the cathedral:

All the photos in this post were taken at an exhibition called Liège au temps des collégiales (Liège in the time of the collegiate churches) at the ancienne église Saint-André.