You can solve the dome riddle when you are in Sagus Cliffs and it will unlock the possibility to fast-travel through the location's main districts. A chance to solve this riddle appears after finishing the main quest called Cold, calculating Jack, that is after finding Matkina in the Cave of the Last Words.
After meeting Matkina, choose the south exit from the cave, which will take you to a previously unavailable section of the Caravanserai district. You will find yourself near a high wall on which you can climb. Use Speed to finish the climb and get to a big, rocky ledge with the dome.
Interact with the dome and go through the following steps:
- Check what's inside the dome;
- Analyze the interface using Lore: Mystical;
- Try to open the dome using the interface.
The force field will disappear. When you regain control, approach the control panel that resembles a tower and interact with it. Try to decipher the text and then go to the smaller panel located next to this one and:
- Examine the interface carefully;
- Try to remember why this sight is familiar to you;
- Determine the meaning of the interface's elements;
- Launch the network connection with the symbol of star constellation;
- Touch the sun symbol;
- Touch the three eyes;
- Touch the crystal mesh;
- Press the tesseract;
- Examine the network's state;
- Repair the network;
- Launch the network connection with the symbol of star constellation.
Afterwards, you will be able to teleport to a location of your choosing. Also, more portals will be activated in the city (just like the one you appear at after the teleportation) which you can use to move throughout the city.