GUEST: I like to shop estate sales when I have the opportunity, and this particular map I got at the end of the second day of the sale. So it was half price. It was in Charlotte, North Carolina, and I just thought it was very interesting and, if nothing else, would fill a big space on my wall.

APPRAISER: Do you want to say what you paid for it?

GUEST: Sure. I thought it was reasonable at $50.

APPRAISER: I see, uh-huh. Well, it's a wonderful map. In fact, it's two maps. If you start with the upper left corner here, you'll see that this is a separate map which serves as a channel map, or a survey of the port of New York. And here's Manhattan right up here in this corner. Now, this was done by a man named John Montresor, who was hired by the British military. He was an engineer, but he made great maps. An interesting piece of information is, "Surveyed in the winter of 1775." It was the winter of 1776 that the Battle of New York... the British drove the Americans out of the city. So the British were doing surveys of the areas they'd come. This is, like, advance intelligence work.

GUEST: Oh, okay.

APPRAISER: Now, of course, the main map, as you go down through here, goes into all of Manhattan here.

GUEST: Right.

APPRAISER: And any of this can be of military interest. As you get down to this part of the map, you'll see that it's keyed to various landmarks. And, of course, churches would be the most permanent, recognizable building. Here's one of the most recognizable streets, Broadway.

GUEST: Right.

APPRAISER: And it is. It's the broadest street. The separation between the sections... This was not unusual for maps at this time, especially a map that might be used for military operations, because this was meant to be folded. And when you fold all this into one piece like this, it was designed to put into a saddlebag so somebody could carry it on their horse and use it...

GUEST: Oh, very interesting.

APPRAIASER: And flip to the section where they're... are they downtown or uptown?

GUEST: Mm-hmm.

APPRAISER: Now, you also did some research.

GUEST: Well, at one auction, it looked like a similar map I think sold for $14,000.

APPRAISER: The record you have is of a sale that was about 12 years ago.

GUEST: Okay.

APPRAISER: And it was about as far from New York City as you could get.

GUEST: Okay.

APPRAISER: If it sold in New York City, either at auction or retail, it would have been worth a lot more. So I would evaluate this map at about $35,000 to $45,000.

GUEST: Wow, wow, yeah.

APPRAISER: And that would be, you know, retail, what you might make at auction. And like at any auction, you might make a little less or might make a little more.

GUEST: Right.