Tomb Raider I-III Remastered Starring Lara Croft

First hidden rocket: Lud’s Gate, on top of the Sphinx’s head. It’s practically in its forehead.

Second hidden rocket: Antarctica, in an alcove high above where you started the level, accessible by jumping off of the large ship once the dingy has been deployed.

Done in TR3 - Antarctica.

The two rockets are found near the beginning of the stage in separate locations. Use camera mode to figure out where I'm talking about first before working out how to get there (as that part isn't so hard).

At the start of the stage, from the starting position, move slightly ahead and to your right there's a red flag on a stick in front of an ice wall, where you see a large medikit, flares and one of the rockets.

You can get to that rocket by running ahead past the hut, following the stream to the right and above and using the ice bridge to enter the hole in the wall. See the screenshot to see where the hole in the wall is in relation to the ship and the hut.



The next rocket is still around the ship area, but you need to progress a bit further. Using camera mode, from the start of the stage, it is located directly above you, behind where Lara is facing, in the small crawl space.

To get there, wait until you enter the ship, and press the button which drops the boat into the sea. From that button, head back, drop down the ladder, follow the corridor round and up, through the room with the two mini staircase on either side and into the room with a door and a button. From this room, climb up through the ceiling, turn around and run through the corridor, pressing the button to open the door to the outside. From the front of the ship, you should see the alcove ahead. You'll need to jump over the metal "hook" thing that was holding the boat, slide down it a bit and jump onto the ice/snow ahead.

See the screenshot to see where the alcove is from the perspective of the front of the ship.



The achievement will unlock immediately after picking up the second rocket.