Diessa Plateau, another part of Ascalon, was once known as the Diessa Lowlands. Parts of the map also contain places like the Flame Temple Corridor, a Charr dominated area in Guild Wars where they converted human ruins into temples where they performed rituals and sacrifices.. The Breach is another- as the name gives away, is the location of a breach in the Great Northern Wall that allowed the Charr to pass through after the Searing.
As with much of Ascalon, you can find many references to the past game, however there aren't actually many large landmarks in Diessa Lowlands.
Ruins of Nolani
Flame Temple Corridor