On this page of our guide to Uncharted 2: Among Thieves you will find a detailed description of secrets and collectibles available in Chapter 7 - They're Coming With Us. Our step-by-step walkthrough explains how to find all (4) secrets hidden in the seventh chapter of the main campaign.
The first secret is located near the starting point. Just take a look to the right to see an almost completely destroyed building. Inside the building, on the left, there is a secret (on the yellow box).
The first battle will take place in a small square, with a sculpture in the center. Examine the sculpture, and you'll notice a bell. There's a collectible inside the bell - shoot at it so it may fall to the ground.
After crossing the river (after blowing up two vehicles), jump down towards the river while standing in front of the stairs that lead between the buildings. The secret item will be lying on a stony, narrow bank of the river.
The last valuable item is in the square, in front of the temple, just before the end of the chapter. You will find it in the central part on one of the industrial carts.