Fallout 4: New underwater structure discovered; is Bethesda developing a new DLC?

Fallout 4 gamers may have never imagined there could be hidden secrets under the vast ocean close to a raider camp. A gamer, while navigating a character, accidentally dropped it into the sea while clearing a camp and discovered underwater structures. This discovery comes days after a Harpoon was found, hinting at some kind of underwater action.

The structure was discovered by a gamer -- FiveStarFacial -- who posted images of the find on Imgur. The gamer continued to explore the sea bed as his character could breath underwater with the help of a power suit that constantly supplied oxygen.

While underwater, the gamer kept the camera focussed downward to get a clearer vision of the objects around. The exploration led the gamer towards multiple landscapes, reportedly, not present in the main-game (Boston wasteland) of Fallout 4.

To navigate through water, the gamer used multiple custom destination points on the map and reached a lighthouse-like structure. The structure seemed like a gas pumping station, but no access doors were found. However, the map prompted an error message stating: "You can't go that way", suggesting that the underwater sequence could be under development.

After following a long pipeline, the player found a car containing some valuables. Nonetheless, the underwater structure and pipeline hinted that Bethesda may be developing a DLC that could unlock access to the underwater structure.

[Source: Imgur, GameSpot]