<p>The archaeologists used a 3-foot-long, remote-controlled robot which was able to explore the last part of the tunnel.</p><p>By Rossella Lorenzi, Discovery.com</p><p>Hundreds of mysterious spheres lie beneath the Temple of the Feathered Serpent, an ancient six-level step pyramid just 30 miles from Mexico City.</p><p>The enigmatic spheres were found during an archaeological dig using a camera-equipped robot at one of the most important buildings in the pre-Hispanic city of Teotihuacan.</p><p><a href="http://science.nbcnews.com/_news/2013/04/30/17989110-robot-finds-mysterious-spheres-in-ancient-temple?lite">Keep reading...</a></p><p>Read also:</p><p><a href="http://www.ksl.com/?sid=24991654&nid=1014">Little robot makes big archaeological discovery</a> (ksl.com)</p><p><a href="http://www.hispanicallyspeakingnews.com/latino-daily-news/details/unprecedented-discovery-at-teotihuacan-hundreds-of-mysterious-spheres/24160/">Unprecedented Discovery at Teotihuacan Hundreds of Mysterious Spheres</a> (Hispanically Speaking News)</p><p>Explore: <a href="http://news.google.com/news/more?ncl=dzrdaqWZaqmNYpMLOvlC12TwaVVVM&ned=us">4 additional articles.</a></p>