Limansk is by far the most interesting location you'll have a change to visit in "Clear Sky". Don't be afraid by the size of this zone, because this entire level has a linear structure. You'll start the game in the southern area of the map and you'll have to reach the northern exit. You will be dealing with Monolith soldiers, radiation and anomalies along the way. You should also know that you'll be given a chance to fulfill a few side missions.
1) Exit to: Red Forest
2) Exit to: Hospital