JERUSALEM (AP) -- Deep in a 2,000-year-old tunnel system outside Jerusalem, a young woman unearthed a rare oil lamp used in ancient rituals during an archaeological dig.

For Abby Krewson, the discovery is especially gratifying: Krewson is a 10th-grader from Philadelphia participating in a "dig for a day" archaeological experience with her family and a Bible college group.

"I didn't expect to find something like that, so it's very exciting," Krewson said.

Tourists like Krewson pay $25 to spend the day working in ancient tunnels in Israel's Bet Guvrin National Park, about 20 miles southwest of Jerusalem.

Participants do the dirty work, digging and sifting through the ruins, while their fees underwrite the more difficult parts of archaeological work: washing pottery shards, logging finds and publishing papers in academic journals.