| Season Episode: 4x01 |
| Episode: 27 |
| Production Number: |
| Original Air Date: 2010-09-17 |
| Title: Gettysburg |
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| Season Episode: 4x05 |
| Episode: 31 |
| Production Number: |
| Original Air Date: 2010-10-15 |
| Title: Stanley Hotel |
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| Season Episode: 4x06 |
| Episode: 32 |
| Production Number: |
| Original Air Date: 2010-10-22 |
| Title: Hill View Manor |
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| Season Episode: 4x07 |
| Episode: 33 |
| Production Number: |
| Original Air Date: 2010-10-29 |
| Title: Vulture Mine |
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| Season Episode: 4x08 |
| Episode: 34 |
| Production Number: |
| Original Air Date: 2010-11-05 |
| Title: USS Hornet |
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| Season Episode: 4x09 |
| Episode: 35 |
| Production Number: |
| Original Air Date: 2010-11-12 |
| Title: La Palazza Mansion |
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| Season Episode: 4x10 |
| Episode: 36 |
| Production Number: |
| Original Air Date: 2010-11-19 |
| Title: Fort Chaffee |
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| Season Episode: 4x11 |
| Episode: 37 |
| Production Number: |
| Original Air Date: 2010-11-26 |
| Title: Amargosa Opera House |
| |
| Season Episode: 4x12 |
| Episode: 38 |
| Production Number: |
| Original Air Date: 2010-12-03 |
| Title: Olde Fort Erie |
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| Season Episode: 4x15 |
| Episode: 41 |
| Production Number: |
| Original Air Date: 2011-01-07 |
| Title: Pico House Hotel |
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| Season Episode: 4x17 |
| Episode: 43 |
| Production Number: |
| Original Air Date: 2011-01-21 |
| Title: Bonnie Spring Ranch |
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| Season Episode: 4x20 |
| Episode: 46 |
| Production Number: |
| Original Air Date: 2011-02-25 |
| Title: Jerome Grand Hotel |
| |
| Season Episode: 4x21 |
| Episode: 47 |
| Production Number: |
| Original Air Date: 2011-03-18 |
| Title: Yorktown Hospital |
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| Season Episode: 4x23 |
| Episode: 49 |
| Production Number: |
| Original Air Date: 2011-04-15 |
| Title: Sacremento Tunnels |
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| Season Episode: 4x25 |
| Episode: 51 |
| Production Number: |
| Original Air Date: 2011-05-13 |
| Title: Kentucky Slave House |
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| Season Episode: 4x26 |
| Episode: 52 |
| Production Number: |
| Original Air Date: 2011-05-27 |
| Title: Tooele Hospital |
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