The most iconic hill is the Côte de La Redoute, the 2.0 km climb in Aywaille at an average gradient of 8.9% with slopes of over 20%.
For a long time in the 1980s and 1990s La Redoute, at ca.
40 km from the finish, was the breaking point of the race and often the place where decisive breakaways were launched.
In recent years the climb seems to have lost that particular role, as many riders are able to keep up with the pace on the climb and race favourites often wait until the last stages of the race to make a break.

In modern cycling, as in many bike races, the decisive stretches have evolved towards the final climbs of the day.
The Côte de Saint-Nicolas is the last categorized climb of the race, with the top at 6 km from the finish in Ans.
It is a precipitous and atypical climb because it is not part of the forested hills in the Ardennes, but located in the middle of the industrial suburbs of Liège along the Meuse river.
In 2016, the organisers inserted the 600 m cobbled Côte de la Rue Naniot following the Côte de Saint-Nicolas, but preceding the finish in Ans.
This turned out to be a one-off, however, as the race has not used the climb since.

Since the finish returned to Liège in 2019, the Côte de Saint-Nicolas has been removed from the route, and the decisive climbs are once again the Côte de la Redoute, Côte des Forges and Côte de la Roche-aux-Faucons.

Course changes are frequent from year to year.
Climbs are sometimes cut or others included.
These are the climbs in recent editions:
The most iconic hill is the Côte de La Redoute, the 2.0 km climb in Aywaille at an average gradient of 8.9% with slopes of over 20%. For a long time in the 1980s and 1990s La Redoute, at ca. 40 km from the finish, was the breaking point of the race and often the place where decisive breakaways were launched. In recent years the climb seems to have lost that particular role, as many riders are able to keep up with the pace on the climb and race favourites often wait until the last stages of the race to make a break.
In modern cycling, as in many bike races, the decisive stretches have evolved towards the final climbs of the day. The Côte de Saint-Nicolas is the last categorized climb of the race, with the top at 6 km from the finish in Ans. It is a precipitous and atypical climb because it is not part of the forested hills in the Ardennes, but located in the middle of the industrial suburbs of Liège along the Meuse river. In 2016, the organisers inserted the 600 m cobbled Côte de la Rue Naniot following the Côte de Saint-Nicolas, but preceding the finish in Ans. This turned out to be a one-off, however, as the race has not used the climb since. 
Since the finish returned to Liège in 2019, the Côte de Saint-Nicolas has been removed from the route, and the decisive climbs are once again the Côte de la Redoute, Côte des Forges and Côte de la Roche-aux-Faucons. 
Course changes are frequent from year to year. Climbs are sometimes cut or others included. These are the climbs in recent editions:
Liège–Bastogne–Liège