Assassin's Creed II

Assassin’s Tombs are available to you once you complete the memory ‘Novella’s Secret’ in DNA Sequence 4 (refer to “Undertaker” for more information). To locate a tomb, search the map for a icon. If you have not synchronized the view points in that area yet, it will not be revealed to you. You must also have completed through a certain DNA Sequence for them to appear.

You can unlock this as early as DNA Sequence 8. This memory is called ‘San Marco's Secret’ and is located in the restricted area in the San Marco district of Venice. You must first climb the Basilica di San Marco to reach the tomb entrance. It is easiest to use the same ascent that you made in the second memory in DNA Sequence 8 called ‘If at First You Don’t Succeed’. Run along the roof and climb down a ladder and the skull “lever” is against the wall.

For this tomb, your goal is to activate four switches in the four sections of the church before time runs out. When you begin, walk towards the sarcophagus on the ground floor and activate the switch. This will reveal four floor places in the center of the church. Stepping on each will start a timed jumping puzzle. They are not that difficult and the camera shows you the path you need to take. If you think you’ll run out of time, stepping on the floor plate again resets the timer.

Once you’ve activated the four switches, the center of the floor will open up revealing steps. Follow the steps to uncover the tomb. Open the sarcophagus and retrieve the seal. When you exit the church, the achievement will unlock.

Thanks to ElectronicElation for the videos:

Part 1:

Part 2: