These are all of the collectibles (Treasures, Journal Entries, Journal Notes, Optional Conversations) that you can find in Chapter 18. There are no collectibles in the Prologue, Ch. 1, Ch. 4, Ch. 5 and Ch. 7.

0:05 - Optional Conversation #31
0:54 - Treasure #90 (Mughal Stout Vase)
1:15 - Optional Conversation #32
1:51 - Treasure #91 (Small Mughal Dagger)
2:35 - Treasure #92 (Mughal Candle Holder)
2:59 - Journal Note #16
3:33 - Journal Note #17
3:56 - Optional Conversation #33
4:14 - Treasure #93 (Mughal Circular Box)
4:41 - Optional Conversation #34
5:12 - Treasure #94 (Mughal Headdress)
5:36 - Treasure #95 (Spanish Brass Chalice)
6:15 - Journal Entry #24
6:35 - Journal Note #18
7:37 - Journal Note #19
7:56 - Journal Entry #25
8:12 - Journal Note #20
8:46 - Treasure #96 (Mughal Painted Elephant)
9:38 - Optional Conversation #35
10:21 - Journal Note #21
10:58 - Treasure #97 (Mughal Dinnerware)

Check out the full guide: http://www.gamerguides.com/uncharted-4-a-thiefs-end/information

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