Vista achievements and sniper

When you come over here in the level the power of the underworld.

Jump and climb the wall

Walk through the corner of the wall

You will find a key,pick it up.

Go back here and walk near the gate.

When you are inside the gate to the right side you will find a dark room and inside the room you will find ladder to climb.

When you climb up you will be on the top of the building and the vista achievement will be unlocked!

Near the wall will find a sniper!