Antiquities, Alliances and Fallen Empires are among the few sets in Magic that have multiple artworks commissioned for the same cards. Some of the artworks tend to sell for a premium. In the case of the plains tower from the Antiquities printing of Urza's Tower, this version went from $4.85 to $8.76 in a 24-hour period.
Uh, that's weird...
Fact is, the Urza "Tron" lands, Urza's Mine, Urza's Power Plant, and Urza's Tower are always in high demand. Despite being reprinted several times, inclusing white-bordered Chronicles, 5th Edition, 8th edition, and 9th edition, the Antiquities printings are extremely sought after.
But if you look at the comparable white-bordered Chronicles versions, which have the same artwork, you're lucky to see them over $1.50.
Why is this? These Urza lands are quite old, and there aren't many copies of them left on the market. Collectors have eaten up a lot of copies and many Modern players like to have them to "pimp" their decks. Since you need four copies of each Urza land for a deck, they tend to be bought up in bunches.
Like Reserved List cards from Arabian Nights, Alpha, Beta, Unlimited, and Antiquities, you'll see these guys a lot on MTGStocks' interests page. While these black-bordered versions are awesome, their prices are so unstable that I don't really like to invest in them. After all, I already have plenty of Chronicles copies... and they work just as well to play with :)