Rockopolis

Rockopolis is an unmarked location in Fallout 3.

Background
Rockopolis is a hidden underground settlement that was abandoned sometime before the year 2277. It is located at the western edge of the Capital Wasteland, north of Girdershade and southeast of the yao guai tunnels. An easy way to locate Rockopolis is to head directly west from Smith Casey's garage. Eventually the Lone Wanderer will encounter a ravine blocking the path. Drop into the ravine and traverse it forward to Rockopolis. The most noticeable feature outside Rockopolis is the multicolored plastic triangle pennants hanging from the rocks, but the bright light emanating from the ladder entrance at night should make Rockopolis easy to spot. There is no visible door. The player character must activate the large boulder in front of the pennants (left of the tree).

There is a random encounter spawn point directly in front of the entrance.

According to files on Herbert Dashwood's computer and the accounts of The Adventures of Herbert "Daring" Dashwood on Galaxy News Radio (the "Black Widow" episode), Rockopolis was once a hidden underground village. The inhabitants would only allow outsiders in if they presented a secret knock. The leader of Rockopolis at the time was King Crag. Herbert accidentally led Penelope Chase, the slaver leader from Paradise Falls, to Rockopolis. According to Herbert Dashwood's computer, the incident led to the enslavement of the city's population and the destruction of the city itself. The fact that the population was enslaved is confirmed by the note found here. Part of Rockopolis is blocked off by a pile of rocks, however there is nothing behind the rocks and it is easy to get stuck.

Exterior
The entrance is a boulder that can be interacted with like any other door or entrance. One dead tree is on the right of the entrance, two are on the left. And as the attached pictures show, there is a length of bunting above the boulder. It is easiest to find at night, as there are lights glowing on the rock face as you approach it from the east. The entrance is very close to the center of that particular square on the map. A random encounter location is near the entrance. There is a string of multicolored plastic triangle pennants (much like those found in Little Lamplight) above the entrance boulder.

If you approach from above, you'll see a small canyon - keep looking down - you'll notice a soft glow. Jump down and you'll have the option of entering Rockopolis without ever seeing the exterior.

Interior
The only accessible section of Rockopolis is now a small area with some random objects. The tunnel to what was the rest of Rockopolis itself is permanently blocked by rocks. The area has the appearance of a cave dwelling, but lacks any beds. The corpse of Argyle can be found near the cave in.

Notable loot

 * Rollings -- We're done is a holotape found on a desk near the ladder.
 * Bobblehead - Unarmed is located next to Argyle's body, a reference to his use of martial arts during his adventures with Herbert "Daring" Dashwood.

Related quests

 * A Manhandled Manservant

Appearances
Rockopolis appears only in Fallout 3.

Behind the scenes

 * In an interview with lead designer Emil Pagliarulo, he incorrectly stated that Rockopolis was located near Paradise Falls

Bugs

 * It is possible to become stuck in a small pit if the player climbs on the rocks that are to the left of Argyle's body. To escape on PC turn off collision in the console with the command. To escape on Xbox 360 and PS3 versions, head to the end of the pit behind the rocks and jump up them till you're on top, head back left (jumping if necessary) until you're clear of potential obstructions, then simply walk back down.
 * Argyle's body may not appear upon entering.