KF2 Catacombs Collectibles: Every Necklace Location
Catacombs is one of the classic Killing Floor 2 survival maps, set in an old crypt with a bones chapel, coffin-filled crypts, a cistern and a cave. This guide by a Steam community author shows where the hidden collectibles (the necklaces behind the Catacombs achievement hunt) are placed, area by area, with a screenshot for each. Some of them are very well hidden, so use the pictures to confirm you are looking at the right spot. For more collectible maps see The Descent collectibles and the achievements page.
I have fond memories of this map, mainly holding out at the entrance and in the bones chapel. I still remember that some necklaces were well-hidden...

Catacombs Cash
Ingresso Cavernoso (entrance)
On the scaffold on the right
Under a red generator on the right
On the scaffold leading to the crypt on the right
On the ladder just next the previous collectible
Capella della Ossa (Bones chapel)
On a pillar on the right
On the left wall
On the left altar
Hanging on a light on the right
Tomba del Cavaliere (Knight Tomb)
Behind a fence, on the right
Crypta dei Frati (crypt with all the coffins and corpses)
Behind the scaffold connecting the chapel to the stairs crypt and cave
Hanging on the ceiling, on the right of the previous collectible
On a little ridge, in front of the stairs, just after the previous collectible
On a corpse at the bottom
Between boxes next to the trader
On the top of a coffin
Behind a trashcan where you connect with the Tomba del Cavaliere
Stairs connecting the citern to the crypt
On the entrance
Under the passageway
On a ridge near a tentacle
Antica Cisterna (Antique citern)
Top of the stairs connecting to the crypt
A little further down from the previous collectible, under the red pipe
Hanging on the ceiling
Hanging on a pipe, very hard to see, above a slide
Between two red pipes
Behind a generator just after the previous collectible
In a blocked entrance
Behind a grate
Cave
Behind the trader
Hanging on the ceiling
In a boat
Source
Based on the Steam community guide by Vic=HKC= (CC-BY-NC), published 21 May 2023.