The Ark watchtower
The Ark Watchtower was my favorite place to enjoy the sunset. The view of Ichan Kala and the city of Khiva is magnificent. On the horizon, we can also distinguish the other minarets. If you have visited the watchtower during the day, make sure to keep your ticket so that you can go back for sunset.
The minarets are great to enjoy a higher view of the citadel. However, they usually can not accommodate more than 5-6 people. The first part is not lit (a mobile flashlight will do), the climb is steep and the passage narrow. However, the view is beautiful!
The city walls
The city walls provide access close to the Ark. Although the view is less impressive, it is a good, free alternative, away from the crowd. Access is via the broken stairs at the north entrance. After entering the city gates, take the stairs on the right; these will lead to the Ark (no direct access).