Pick up the harpoons in the alcove to the right. Exit the room and get some more flares in the sunken window sill on the left. When you pick them up, you see a wide-angle view of the scuba diver in the room beyond. Continue along the hall through the next doorway. On the left there's a door marked 'Restricted Area', which is locked. Follow the hall to the right and around the corner. To the right there is a large window looking out over the sea bottom. You can see a second yellow tunnel, with a large hole in it's side, running parallel to the one you're in. If you're quick you may also see a small submarine zip past.

Go through the opening opposite the window on the left. Kill the sniper in the raised hallway across the pool. If you don't get him, he disappears to the left and can be ignored for now. Go around the pool and use the wheel on the wall. This opens the "Restricted Area" door you saw earlier. If the sniper is still alive, he'll come through that door and around to where you entered the pool room. Wait for him and then finish him off.

Before going up to the ledge where the sniper was, jump in the pool and do some exploring. Begin by treading water facing the doorway where you came in. Swim downwards and outside the man made structure into a large cave area. Go under the yellow overhanging edge of the structure, then up to a rock ledge underneath some netting, where you'll find a bunch of harpoons. Get them and swim back to the pool to breathe.

For the next dive, start with the entrance behind Lara. Swim down, then head off to the far left corner of the underwater cave. Swim up through the square opening, and pull the lever in one corner to open the white bars. A scuba diver comes out from behind the gate to see what's happening. Harpoon him or swim through the connecting tunnel into the room he came from, climb out of the water and shoot him from there. Pick up some harppons and 3 boxes of shells from around the edge of the opening.

Swim back to the big pool, climb out of the water and exit into the hallway. Go to the right to the "Restricted Area" door you opened earlier. Pick up a small medikit on the ledge just inside on the left and then follow the hallway all the way to the end and pick up some MP5 clips. Near those clips is a short ramp above a pool. Slide into the water, find the lever to the left of the underwater gate and pull it to open the gate.

This sets off alarms and alerts 2 scuba divers. Swim out of the cage, forward and up under the yellow structure. Here you can climb out of the water and shoot the divers from above. Inside this room you'll find harpoons and flares on the metal ledges. Press the button in one of the alcoves to open the white gate outside. Find the movable crates (the zoological ones) and pull the one on the right to the right. Go around it and push the crate on the left in either direction.

Go into the alcove behind it to pick up a small medikit and get a glimpse of a sentry on duty beyond. Jump back in the water and swim down toward the cage where you entered this area. Don't enter the cage - swim upwards outside it and pick up the Uzi clips on the yellow metal ledge opposite and above the cage gate. Head into the cage and surface for air. Now exit and swim back to where you got the Uzi clips. Turn right and swim along the side of the yellow structure into the square opening beyond. Follow the twisty tunnel and pick up 2 bunches of harpoons on the way.

When you come out the other side, a pair of friendly dolphins will greet Lara and the camera will show a wideangle view of this area as the current carries Lara to the left. Don't fight it. Look for a square opening near the corner and swim inside. At the end of the tunnel, go left and climb out onto a ledge. If you do doggie paddle in the water for a couple of minutes, one of the friendly dolphins will give Lara a boost out of the water!

This is Secret #1 - harpoons and 2 large medikits. Go back into the water and swim forward to another opening where you can surface. Immediately draw weapons to kill the sentry you saw earlier through the fence. Take his MP5 clips then jump off the ledge into the water. You'll find more harpoons and a small medikit at the far end of the narrow channel and at the opposite end, there's a break in the netting, where you can swim back to the pool where you started.

At the surface of the pool, position Lara so the green crates are on Lara's right and swim down and straight ahead to the gate. The current sweeps Lara into the tunnel to the next area. Swim straight in from the opening and up inside the yellow funnel to the crane control room where you can get air. Climb out of the pool and pick up a large medikit and harpoons. If you look out the window, you'll notice a sub descending and releasing 2 scuba divers. Also take note of the two receptacles, blue and yellow, on the ledge at the other side of the room.

You can swim down and draw the divers up to this opening to kill them. Or go head-to-head with your harpoon gun. After killing the divers get air and make a few forays into the pool for goodies, coming back to this opening for air after each one: Face the tunnel where you entered from the previous area. Swim down toward it then up to the top of the yellow structure to find some grenades. There's also a rocket on top of the metal beam the crane is supporting.

Take another swim from the control room down toward the crane, then up the rock wall to the right of the crane, where you'll find a small cave. (It may take you a few dives to locate this - if you go much beyond the crane you'll trigger the next action sequence and have to deal with more divers. Also, note that the very tempting mini submarine floating nearby is out of Lara's range - she can't swim against the currents protecting it.)

Inside the cave are some flares and a Circuit Bulb. Return to the control room for air and then swim down to the bottom then up the rock wall, staying to the left of the crane as you pass it. Beyond the crane there's a wide support pillar with round grates and the "Slinc" logo on it. Swim past this toward a rectangular rock pillar. Now head for the ceiling. Just above the rock pillar there's a small, square opening in the cave ceiling surrounded by rusted metal. Swim in here for air and pick up a small medikit and a second Circuit Bulb.

Swim straight down from the small opening toward the globe light below and pick up a bunch of harpoons. If you have enough air, turn left and swim back to the control room (follow the globe lights along the sea bottom). Or swim back up to the small opening first, then return to the crane control room.

Place the two Circuit Bulbs in the receptacles on the wall that you found earlier. This opens a small, yellow door on the far side of the underwater cave marked "Restricted Area". Swim down, then up past the crane, following the globe lights on the sea floor toward the door you just opened. When you near the large cave opening on the right, the current sucks Lara down and you see another submersible descending to deliver 2 more scuba divers. If you need air, head for the small opening in the ceiling of the cave. Then confront the divers. (This may occur earlier, when you're exploring around the crane).

When the coast is clear, approach the small door you just opened but instead of going in, swim into the narrow tunnel just to the right of it. This is Secret #2. Follow the tunnel to a cave and go straight through it to an opening in the floor. Swim along this tunnel to a room where you can surface and pick up 2 bunches of harpoons and a small medikit. Swim back out to the secret cave and pick up the flares on the bottom.

Be careful when getting the shotgun shells nearby. When you take them, a small submarine speeds down the hill, hitting Lara unless she gets out of the way in time. So position Lara facing either wall, pick up the shells and quickly swim forward out of the way. When the sub crashes into the wall, it opens up a way into the cave beyond. Get air first if you need it, then swim inside to find the rusted hull of a sunken submarine.

Pick up the Desert Eagle Pistol and 2 sets of ammo on top of the sub. There's a small, square hole in the ceiling above the conning tower of the sub where you can get air. Swim out of the cave, turn right beyond the small yellow sub and follow the tunnel out to the main cave. Make a U-turn to the right and swim through the "Restricted Area" door. The current will carry Lara along to the top of the passageway.

Swim up to the yellow opening at the top of the passageway and climb out into a hallway with bars at the far end. About halfway down the hall on the left is a room with a window and a locked door. Draw pistols and make some noise to get the gunman's attention. Kill him when he opens the door.

Go in and pick up a small medikit and flares inside on the right. Looking out for the trapdoor in the middle of the floor, go behind the radar screen to find a a bunch of harpoons. Press the button near the door to open the bars at the end of the hallway.

Exit the room, turn left and continue into an enclosed walkway overlooking the sea floor. Each of the 2 red wheels on the right opens one of the small doors on the cave wall outside, letting in 2 huge mutant fish. Turn the wheels one at a time so you don't have to deal with both fish at once. After turning the first wheel, continue along the hallway and pick up a rocket and a small medikit and get a glimpse of another rocket and the goings-on inside the Research Lab.

Return to the control room and fall through the trapdoor into the water. Harpoon the first big fish, or get it's attention and then swim to the yellow opening, climb out and shoot it from the ledge with pistols. Jump back in the water and go into the main cave. Face the white underwater structure and swim to the far right corner. Swim through the small, square opening underneath the rusted metal support and then turn left and wim upwards. This sets you back in familiar territory where you can release the second giant fish using the second hand wheel and then repeat the previous exercises to kill it. Or take your life in your hands and go for both fish at once!

With both fish out of the way, you can make a few pick-ups: From the yellow opening, swim down and through the small square opening back into the underwater cave. Swim in a little and then turn around. Swim behind the dark bluish rock to the right of the rusted metal support. Here you'll find some harpoons. Get some air and then swim across the underwater area toward the white enclosed walkway.

Swim down between the leftmost support pillar and the one next to it. Here you'll find a narrow tunnel in the rock wall. Swim inside to get the attention of another mutant fish. Draw it out into the open area to harpoon it. After you've dealt with the fish, swim back down the tunnel into a small room with a window looking into the Research Lab. Pick up a large medikit, grenades and the loaded Grenade Launcher. This is Secret #3. Swim back out to the pool and up the white funnel for air when you're done.

Now head for the small square doors you opened earlier using the wheels in the walkway (where the first two mutant fish came from). Swim through the door on the right and pick up the Mutant Sample. Swim out and through the left door to get another vial of the stuff and continue along the tunnel to the lab.

Surface and climb out of the water. Follow the ramp down to a room with tanks and cages containing various mutants. Move the 2 green crates (one is just to the right of the door as you enter). Underneath one you'll find Uzi clips. Behind the other is a machine. Place one of the Mutant Samples into this machine. Place the other sample into the identical machine in the other corner. This causes water to flow into a pool elsewhere.

Return up the ramp to the pool where you entered the lab. Go up the stairs, take out the gunman on duty there and grab his small medikit. Follow the walkway around the edge of the pool. Climb to the upper walkway and pick up the rocket you saw through the fence earlier. Climb up to the small ledge above the rocket and get some grenades. Then jump into the pool.

Pick up the Hand of Rathmore artifact from the low pedestal. This opens the door in the side of the pool. Get air if you need it, then swim through that door into a dolphin tank. Pull the lever on the left wall to open the door at the other end of the tank, letting in a mutant fish. Harpoon it or lure it up to the first pool, climb out and shoot it.