Into the depths

Kfr 01: Discovery.
A small submarine accidentally discovers a giant skeleton in a cave in the abyss.
An endless Lovecraftian ladder seems to descending into the depths.

Kfr 02: Descending.
The submarine goes down deep in the tunnel that opens in the giant skeleton throat.
Giant statues (tombs?) and endless ladders can be glimpsed along the walls.
In the bottom it begins to appear a strange greenish phosphorescence.

Kfr 03: The lost city submerged.
A giant cave.. a phosphorescent city.. and ...yes, you can see the Titanic Name on the side of the gigantic wreck.. (but his carcass was not lying at the bottom of the ocean far from there?).

Kfr 04: Close encounter.
An endless city... It looks like a graveyard of ships.
Suddenly a dangerous creature appears... this probably won't have a happy ending.