There are twenty Memory Cards scattered throughout the game in North Rook and South Rook. Finding these memory cards will help you unlock a signature weapon, and get you an achievement as well.
Here are all of the memory card locations, with coordinates. Look on the upper right hand of your map for your current coordinates to help you find these.
Memory Card 1 – Location: North Rook, Coordinates: X: 402, Y: 680
Memory Card 2 – Location: North Rook, Coordinates: X: 438, Y: 795
Memory Card 3 – Location: North Rook, Coordinates: X: 503, Y: 737
Memory Card 4 – Location: North Rook, Coordinates: X: 457, Y: 627
Memory Card 5 – Location: North Rook, Coordinates: X: 580, Y: 753
Memory Card 6 – Location: North Rook, Coordinates: X: 540, Y: 683
Memory Card 7 – Location: North Rook, Coordinates: X: 648, Y: 743
Memory Card 8 – Location: North Rook, Coordinates: X: 688, Y: 787
Memory Card 9 – Location: North Rook, Coordinates: X: 658, Y: 642
Memory Card 10 – Location: North Rook, Coordinates: X: 637, Y: 530
Memory Card 11 – Location: North Rook, Coordinates: X: 746, Y: 779
Memory Card 12 – Location: North Rook, Coordinates: X: 730, Y: 638
Memory Card 13 – Location: North Rook, Coordinates: X: 808, Y: 655
Memory Card 14 – Location: South Rook, Coordinates: X: 487, Y: 427
Memory Card 15 – Location: South Rook, Coordinates: X: 443, Y: 384
Memory Card 16 – Location: South Rook, Coordinates: X: 336, Y: 477
Memory Card 17 – Location: South Rook, Coordinates: X: 379, Y: 329
Memory Card 18 – Location: South Rook, Coordinates: X: 279, Y: 432
Memory Card 19 – Location: South Rook, Coordinates: X: 214, Y: 375
Memory Card 20 – Location: South Rook, Coordinates: X: 525, Y: 443