Chamberlain takes you there when you ask him to. There's constant fighting in the streets here - you don't have to get involved.
1. Starting point.
2. When you go down the stairs, Zoltan talks to you.
5. Hospital (enter it from the square if you support the Squirrels and from the back if you are neutral). You'll get inside in phase 4 of Q5.109. Hope Burns Bright. In a locker there's a book on Striga.
6. Notice board: cementaurs, bloedzuigers, bruxae, garkains, wraiths.
7. Scoia'tael hideout. There's a book about Striga in a chest.
9. First group of refugees.
10. A hut. A diseased woman there will tell you about Cementaurs if you give her something to eat. In a wardrobe there's a book Against Nonhumans.
11. Order quarters.
15. Hut. Diseased Man will tell you about Garkains for 5 orens.
16. Kalkstein's lab. In a chest there's a book Alzur's Double Cross. Kalkstein won't be here until you kill the mutant in phase 9 of Q5.110. Her Highness the Striga. Ask him about the Striga for a few hints. You can meditate here (when Kalkstein is present).
17. Group of refugees.
18. Gate to the Dike.
19. Hut. In a cupboard there's a book: The Aftermath of the War.
20. Fighters - virtually unlimited number. Don't try to fight them, they will gradually disappear when you progress certain quests.
22. Cementaurs and Graveirs.
23. Remains of a barricade. You'll get here in phase 15 of Q5.109. Hope Burns Bright.
24. More barricade remains.
25. Gate to the Swamp Cemetery.
27. Barricade to smash.
28. Tower. Zahin Schmartz lives here now. You can meditate here.
30. Barricade to smash.
31. Barricade to smash.
33. Barricade to smash.
34. Barricade to smash.
Important: Barricade's placement varies depending on which side you're on. Use Aard to smash them.
After going to the cemetery, you'll be able to move around Old Vizima freely (there won't be any more battles going on). This requires you to complete a quest Q5.109. Hope Burns Bright (if you support the Squirrels) or Q5.124. Under a Fiery Sky (if you're neutral), or Q5.126. The Flame That Cleanses (if you are with the Order).