<p><strong>Standing on wooden steps that protect a 3,300-year-old stone staircase, Egyptian antiquities chief Zahi Hawass poses in 2009 in a mysterious tunnel that links the ancient tomb of Pharaoh Seti I to ... nothing. </strong><br><br> After three years of hauling out rubble and artifacts via a railway-car system (rails visible at left), the excavators have hit a wall, the team announced last week. It seems the ancient workers who created the steep tunnel under <a id="v6i6" title="Egypt" href="http://travel.nationalgeographic.com/travel/countries/egypt-guide/">Egypt</a>'s <a id="fm46" title="Valley of the Kings" href="http://www.nationalgeographic.com/history/ancient/valley-of-the-kings.html">Valley of the Kings</a> near Luxor (<a id="vtb:" title="map" href="http://ngm.nationalgeographic.com/ngm/0301/feature4/map.html">map</a>) abruptly stopped after cutting 572 feet (174 meters) into rock.<br><br> Hawass, also a <a href="http://www.nationalgeographic.com/field/explorers/zahi-hawass.html">National Geographic Society explorer-in-residence</a>, believes work on the tunnel began during the pharaoh's 15-year reign (1294-1279 B.C.), but after the tomb above it was already complete. Work may have stopped when Seti I died.<br><br> Archaeologist Mustafa Waziri, regional director for the Egyptian antiquities council, said: "I think they were planning to make another burial chamber down there. Suddenly they stopped. But the condition of the stairs is amazing." <br><br> (The National Geographic Society owns National Geographic News.) <br><br><em>—Andrew Bossone and Ted Chamberlain</em></p>