This is hidden to the left past a rock, hang off the edge of the cliff to get there (or jump).
Follow the path to the right, it'll lead you to a muddy slope to slide down. At the bottom go outside and drop down to the right a couple of times until you get to a plank bridge, cross over and then climb through the gap. You'll see a helicopter fly by.
Climb up the right side of the waterfall then slide down it.
Sliding down the slope jump to the ledges on the left at the bottom.
If you jump off the top of this platform into the water below you can get yourself a trophy.
|Perform an impressive dive from the cliff near the old railroad tracks|
Slide back down the slope this time aiming for the ledges on the far side. At the top squeeze through some roots then attempt to leap over to the next set of ledges across the next slope. As you come off the end of the slope use your rope to grab onto the bottom of the bridge. Swing to the some ledges on the right behind a couple of waterfalls.
Through the cave you'll enter an arch of the bridge with some metal grating over the side.
Climb the grating and flip over at the hole to climb up the outside to get up to the top of the bridge. To help Sam get across the gap all you have to do is shove the cart along the tracks towards him.
Look up at the broken ladder that Nadine's looking at. After boosting Nadine up climb the pipe and transfer to the ladder. Get up to the top then jump to the signal that Sam's hanging off, move along to the other end then turn around and swing towards the ledges. Clamber over Sam and rope swing onto a slope with a jump to a second slope.
Hang off the edge of the cliff on the left and start climbing the green handholds.
Climb up the rope that Sam left behind then swing down into an encounter.
As you've got no weapons to start with you'll first want to help Sam out with the shotgun guy on the right, grab his gun and you can start shooting the other enemies hiding on a train cart. There'll be another couple in the tunnels on the right before reinforcements arrive and start swarming you. Watch out for the guys wearing gas masks breathing heavily as they'll just run straight for you and choke hold you which damages you and leaves you vulnerable to getting shot by other enemies. I'd certainly advise that you keep on the move rather than just hunker down at the start as you can actually go into hiding if they lose track of you in the tunnels.
|Getting to Know You|
|Listen to all optional conversations|
Once you're done squeeze out through the gap in the rubble and slide down a slope. Quickly rope swing across to another slope and rope swing off the bottom of that one too. That'll lead straight onto a set of three more slopes before you jump to a ledge and climb up a piton wall.
|Pics or It Didn't Happen|
|Take a photo at all the photo opportunities|
Climb up the ledges on the right side.
Where you can climb down instead of up to get to the treasure on a platform just above where you emerged from the tunnel.
Climb up until you see Nadine and Sam then use your rope to get up to them as the tower you're attached to falls off. Up the platforms at the back to some railway tracks.
Push the cart along the tracks then turn the points and push the cart down to the wall. Hop over the gap in the wall then boost Sam up to the ladder in the corner on the right. Jump back out the wall and shove the cart back along the track, turn the points again and push it into position below Sam. Climb up the crate he drops.
After climbing up go into the tunnel Sam came out of to find the treasure at the top of the ladder.
Climb up to the top of the train tunnel outside and make your way around the corner. There's a rope swing ahead.
Instead of jumping straight across swing back towards beneath where you jumped from and land on a ledge there.
Inspect and look at the bottom of the treasure for a trophy.
|Shake For Your Fortune|
|Ask Skeleseer a question|
Get back onto the rope swing to get across to the side of the building, climb up and through the slightly opened windows to enter an encounter.
Surprisingly enough this fight is all about that helicopter, the enemies on the ground are just obstacles to you shooting it down with RPGs or some very well aimed C4. To find the RPGs you have to open up the orange lock boxes that are scattered throughout the map, the C4 is in the already open white boxes (also good for tracking the chopper). It'll take a couple of hits before you can run up beneath it and use your ropes to latch on.
There is a trophy to down the helicopter without killing any of the ground troops so make sure to have a few rockets ready before you start firing at it.
|Right Under Your Nose|
|Destroy the helicopter without defeating any other enemies|
Make sure to open the five lock boxes before you grapple onto the chopper, preferably before you start shooting it down at all.
On the back of a truck next to the stairs leading up to the walkway. Contains an RPG.
Along the rocky back edge near an oil tanker truck. Contains some grenades and a Type 95.
Inside the main building on the left. Contains a US-AN 12 Auto Shotgun and some grenades.
|Picks or It Didn't Happen|
|Open every lockbox|
Each time you hit the chopper some more reinforcements will arrive so watch out for those (or just save up the RPGs until you have several). After three hits it'll become vulnerable to being grabbed by your rope, get into the open or on top of a train car and throw your rope at it. Don't worry about any ground enemies at this point, just keep climbing up to the chopper to start a quick melee fight with Orca.