FOR A DECADE NOW, the market for what some call "explorabilia"—antique objects used by adventure legends like Lawrence, Robert F. Scott, Captain James Cook, and David Livingstone—has been chugging quietly along, driven by a worldwide network of fervid collectors who probably number no more than 50 and prefer to remain anonymous, mainly because of the monetary values involved.

The goodies get sold in various ways, often through a sprawling private network of explorers' families, and friends working on the families' behalf. Some sales are handled by antiquarian bookstores and on eBay, but the Christie's auction is far and away the subculture's biggest show, accompanied by a fat, lavishly produced catalog and a treasure trove of historically significant objects. Starting small in 1996, the auction has become a tribal event for the planet's explorabilia buffs, with nearly $3.7 million changing hands during last September's one-day sale alone.

Outside sent me to London to check out the 2006 offering, authorizing me to spend up to $1,500 to snag a cool souvenir for the home office. I wasn't optimistic I could afford anything. Compared with other Christie's sales, the explorabilia totals aren't that huge, but the prices for individual items can be amazing. "Christie's art auctions make lots more money than we do," says Nick Lambourn, 50, one of the sale's two founders. "But few auctions anywhere get collector interest the way ours does. Who wouldn't want Henry Morton Stanley's map of the Congo, with the map's blank portions sketched in by Stanley's own pencil during the 999-day trans-African expedition? For a certain kind of collector, these objects are sacred. That's really fun."

Not to mention lucrative: In 2002, Stanley's map sold for roughly $121,000.

Lambourn and his fellow cofounder, 49-year-old books-and-maps specialist Tom Lamb, employ a unique combination of luck and carefully cultivated relationships to land their swag. Together, the small, dark-featured Lambourn and the tall, auburn-haired Lamb manage, every year, to gin up an absolutely transfixing mix of museum-worthy and oddball curiosities to drop into the sale's larger pot of books, maps, photos, and paintings.

Examples? How about Antarctic explorer Sir Ernest Henry Shackleton's ragged ration bag, a cotton sack that carried his Christmas pudding during his 1901–04 Discovery expedition and which sold for $6,497 in 1997? Or the hollow-coconut drinking cup Captain William Bligh used after he'd been bounced from the HMS Bounty in 1789? (2002 sale, $142,000.) Other lots have included Captain Cook's antimony cup, a squat drinking vessel made of antimony alloy. From this, the great South Seas explorer consumed red wine that, having reacted with the metal, created a potion "with purgative qualities." This handy laxative system fetched $392,392 in 2005.

One of Christie's most famous auctions, held in 1999, involved the sale of relics recovered at the death site of Robert F. Scott, who perished in 1912, along with all five of his men, after a failed attempt to beat Norway's Roald Amundsen to the South Pole. Lamb and Lambourn acquired them from Lady Phillipa Scott, Scott's daughter-in-law, then in her seventies and living at Slimbridge, the family estate in Gloucestershire, England.

"A few years ago, we visited Lady Scott," Lamb recalls, "and she pulled out this leather trunk from beneath a bed, and it was filled with Scott's possessions."

Inside were the explorer's personal effects, recovered when his frozen remains were found by a late-arriving British rescue team—among them, a brass pocket watch, snow goggles, a pennant, Scott's diaries, geological specimens, two briar tobacco pipes, and a bag of tea. At auction, the boodle sold for an astounding $514,700.