The last expanse of the Hammer Valley area. It contains an abandoned control building which goes along a path to an entrance of the Bergmann Tunnels. This map introduces some unsettling story elements provided the player explores enough.

Story

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General
Map Name	reserve3
BSP Name	infra_c2_m3_reserve3
Stalburg Map	reserve3
Statistics
Photo Spots	8
Corruption Spots	3
Repair Spots	0
Mistake Spots	0
Geocaches	2
Water Flow Meters	0
Connected Maps
Previous Map	reserve2
Next Map	tunnel1

This is perhaps one of the least populated areas in the entire game, but that doesn't mean there is any lack of story. In fact, some of the more unsettling parts of Infra can be revealed here if the player only looks hard enough. However, this level is perhaps more notable for one of Infra's harder puzzles - the switch puzzle to open the gate to access the tunnels. Most long-time players will draw a graph to combat this, but aside from that, it's an easy level, albeit one with some hard-to-miss areas behind locked doors and hidden keys.

Mark continues his trek to the Bergmann Tunnels, passing through Hammer Handle Cave. Further ahead, his path is impeded by another gate, which must be operated from the abandoned control center nearby.

After switching the gate to the correct settings, he passes through and enters the vicinity of his next inspection target, the Bergmann tunnels. Mark enters through a flood door which immediately shuts behind him, leaving the only way out through the tunnels.

Locations

Hammer Handle Cave

A small cave connecting the path from the dam to the nearby control building. At some point, two people, Hanss and Lukas, passed through the cave in effort to enter the old tunnels, dismissing stories as urban legend. Another note left by the same Lukas can be found in the next map. Their fate is unknown.

Control Building

A small building that contains a locked-off garage, a small office, and the controls for the gate. If Mark picked up unmarked keys from the caves earlier, he can access the garage of the house, and discover a dead body. The body is covered, and the sheet has an unusual alphanumeric code written on it (related to the ARG). Mark will be alarmed and call Paul, who will contact the police to investigate the body, and tells Mark to continue.