In GoldenEye 007 there is a small outpost at the base of the mountains on the opposite side of the dam's reservoir. This is commonly called "the island" by the game's fanbase. It can be seen from anywhere on the dam, but the easiest way to take a peek at it is to zoom in with the sniper rifle at the end of a dock. The island is home to a guard tower, which uses a unique style not used for the other towers in the level, and an inactive drone gun. This drone gun is actually modeled as part of the level background—it's not a prop, so it can't fire.
The only things confirmed to have been placed on the island are a lone patrolling guard and body armor – a reward for exploring. There is a pad on the wall inside the lower section of the guard tower—it (2759) is found between the pads used for the mission's alarm objects. There are also pads that would've been used as nodes for one or two patrol routes around the bottom of the tower and its walkway, but there is no defined path for these anymore.
Only a few areas of the island have collision in the final game—interestingly, there are three pads placed on a section of ground which still has collision near the mooring posts.