Dishonored 2 has 10 Decorative Objects for the Dreadful Wale. Finding all locations unlocks the "Souvenirs" Trophy & Achievement.

The Decorative Objects are scattered across the 9 main missions. In between missions you will come to the Dreadful Wale (your ship, the hub area). Here in the starting room you can see the decorations that have been found (sitting on the shelf).
All of these collectibles are missable because there is no mission select! You are advised to make a manual save at the start of every mission. In case you missed one you can reload that save and replay from there. Without a backup you'd have to restart the entire story if you miss one.
Everything can be reached as either Corvo or Emily. It doesn't matter what character you choose. When playing as Corvo you should upgrade the Blink range as soon as possible to reach certain places.

The collectible progress is only saved when you trigger an auto-save or manual save. If you die without saving you have to pick them up again. It's best to save after every collectible.
Mission 6 has two Decorative Objects, every other mission has exactly one. Some of them require you to kill certain enemies while others are physical collectibles that you need to pick up.

Each mission features an open world design. This means you can free roam as you like and reach any place at any time, but only if you don't finish the mission. Once you leave the mission you cannot go back. This also makes it easy to work on multiple collectible types at once (for trophies you need all Decorative Objects, All Paintings, All Journals and Audiographs on the Dreadful Wale). For example: go after the one Decorative Object and then collect the Paintings. The other collectibles are on the Dreadful Wale in between missions.

TIMELINE:

#1 - Mission 1 - 0:05
#2 - Mission 2 - 0:37
#3 - Mission 3 - 1:10
#4 - Mission 4 - 2:47
#5 - Mission 5 - 3:48
#6 - Mission 6 - 4:30
#7 - Mission 6 - 5:15
#8 - Mission 7 - 6:04
#9 - Mission 8 - 6:45
#10 - Mission 9 - 7:14

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