<p>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.</p><p>After three years of hauling out rubble and artifacts via a railway-car system (rails visible at left), the excavators hit a wall, the team announced in July. It seems the ancient workers who created the steep tunnel under <a id="fdle" title="Egypt" href="http://travel.nationalgeographic.com/travel/countries/egypt-guide/">Egypt</a>'s <a id="a1qh" 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="lq2t" title="map" href="http://ngm.nationalgeographic.com/ngm/0301/feature4/map.html">map</a>) abruptly stopped after cutting 572 feet (174 meters) into rock.</p><p><a href="http://news.nationalgeographic.com/news/2010/07/photogalleries/100707-science-ancient-egypt-tomb-tunnel-seti-pharaoh-pictures/"><strong><em>Full story and more pictures: "Secret Tunnel Explored in Pharaoh's Tomb."</em></strong></a></p>