Lower Reaches Overview - Baldur's Gate 2

The Lower Reaches is a zone that's found below the Temple District of Athkatla; you can only access this map during (and after) the Investigate and Destroy the Cult side quest. During this side quest you'll have to agree to help Gaal with retrieving the other half of the rod, doing this will allow you to access this area.

All in all there is not much to say about this map. If you didn't import the item from BG1 you'll find Ashideena +2 in the same area as the broken bridge. There aren't any other notable magical items to be found here.

 

Monster Summoning: Here you will find a container with a couple of gems and scrolls as well as a statue face that you can click on to summon monsters. You can click on this up to 5 times to summon the same group of enemies over and over for a decent amount of EXP.

Broken Bridge: At this location you will find a broken bridge that you'll need to answer a riddle to cross. I've included answers to all 3 questions that you're asked below; alternatively if you'd like to see a Youtube video explaining this puzzle check out my BG2 Athkatla Sewers Bridge Puzzle Video. One thing I will say though is make sure you buff up before crossing this bridge as you'll fight 3 Beholders immediately on the other side.

Answer #1: Life
Answer #2: Time
Answer #3: The current one, for it alone is my choice

Temple: You'll have to visit this temple to acquire the first half of the rod during the Investigate and Destroy the Cult side quest. At the end of this quest you will be able to return the Rift Device to this time and have it destroyed for 47k EXP as well as Saving Grace +3.