On this page of our guide to Uncharted 2: Among Thieves you will find a detailed description of secrets and collectibles available in Chapter 18 - Heart of Ice. Our step-by-step walkthrough explains how to find all (6) secrets hidden in the 18th chapter of the main campaign.
The first secret is lying on the third cylinder, not far from the beginning of the chapter. You'll have to walk on it to complete the chapter. You will find it on the opposite side of a spot where you have to jump towards the brick platform. It will be attached to a wooden board, in the upper part.
You'll collect the second secret when you swing on the first rope available in this chapter. You'll have to get close to the item in order to reach it. Quickly collect the treasure and don't let go of the rope.
The third secret is near the second one. Jump from the rope towards the platform and it will collapse. Then, you will land on the floor below (and use a cogwheel beforehand). This way you will reach a place with several cogwheels. Two of them will be set horizontally. Jump on the first cogwheel and grab its edge. During the first spin, you'll get under the floor. A treasure is hidden there.
Treasure no. four is one of the most difficult to find in the whole game. When you extend the bridges out of the hand and collapse the cylinders, you will reach a darkened place (by swinging on the chain beforehand). After completing several arcade sequences, you will get to area with three cogwheels that can be used as a lift. Use the first one to ride up to the ceiling - don't jump on the next one. Once you get under the ceiling, jump on the rafters (the picture shows the view from the rafters towards the mentioned cogwheels). Only then get to the rocky ledge at the opposite right end of the room.
The fifth treasure is located near the fourth one, but this time it is extremely easy to find, because it lies on your path. After making a jump from the last row of cogwheels, you will land on a rod, and then on a snowy ledge. Go right, not left, and you'll find a sculpture hidden in the shadows. Treasure is attached to the eye of the sculpture (shoot at it).
The last treasure is attached to a giant sculpture which you are trying to reach throughout the whole chapter. It is located in the central part of the crown. One accurate shot from a gun is enough to make it land at your feet.