It was mentioned that the underground passage runs under Feathered Serpent Temple, and the entrance is located a few meters away from the temple at the expected place, deliberately sealed with large boulders nearly 2,000 years ago. The hole that had appeared during the 2003 storms was not the actual entrance; a vertical shaft of almost 5 meters by side is the access to the tunnel. At 14 meters deep, the entrance leads to a nearly 100-meter long corridor that ends in a series of underground galleries in the rock. After archeologists broke ground at the entrance of the tunnel, a staircase, and ladders that would allow easy access to the subterranean site were installed. Works advanced slowly and with painstaking care; excavating was done manually, with spades. Nearly 1,000 tons of soil and debris were removed from the tunnel. There were large spiral seashells, cat bones, pottery, fragments of human skin. The rich array of objects unearthed included: wooden masks covered with inlaid rock jade and quartz, elaborate necklaces, rings, greenstone crocodile teeth and human figurines, crystals shaped into eyes, beetle wings arranged in a box, sculptures of jaguars, and hundreds of metalized spheres. The mysterious globes lay in both the north and south chambers. Ranging from 40 to 130 millimeters, the balls have a core of clay and are covered with a yellow jarosite formed by the oxidation of pyrite. According to George Cowgill of Arizona State University, the spheres are a fascinating find: "Pyrite was certainly used by the Teotihuacanos and other ancient Mesoamerican societies. Originally, the spheres would have shown [sic] brilliantly. They are indeed unique, but I have no idea what they mean." All these artifacts were deposited deliberately and pointedly, as if in offering to appease the gods.
It wAS mentIoned that tHe unDerGroUnD PAsSagE runs uNdEr fEAthEred serPeNT templE, ANd tHE entraNCe Is locateD a fEw MeTers aWAy fRom ThE teMplE at ThE expecteD PLace, delibERatel.Y sEaled witH large boulDERs NeaRly 2,000 yeARS Ago. The HolE that had aPpEaReD DUring the 2003 stOrmS wAs not thE acTUal EnTrAnCE; A VerticAl ShAFt oF AlmOSt 5 metERs by sidE Is the AcCESS tO the tUnnEL. at 14 meteRs dEEP, The eNtrance Leads to a nEArly 100-meter LOng corridoR thAt eNdS in A sERiEs of UNdERgRoUNd GallERIeS in tHe roCk. aFtER aRcheologIstS broKE gRouNd at tHE eNtrance Of The tUNneL, A staircase, and lAdders thaT would aLlOw easy accEss to the subTeRraneAN sItE weRe InStAlled. wOrks ADvANced SlowlY anD wItH PainsTakiNg care; exCaVatIng was donE maNually, WIth spAdes. neARLY 1,000 tonS oF soIl and debriS werE remOvED from tHe tUNNel there Were laRgE sPIrAl seaShelLs, cAt bOneS, pOTtery, frAGmEntS of huMAn SkiN. tHe Rich arRaY oF ObJecTs UnEArthed iNclUDed: WoodeN MAsks CovErEd with iNlAID roCk jade aNd QuarTz, elAbOrate nECklaceS, rIngs, greENsToNe croCodilE teeth and hUmAn figuriNes, crystals shAPeD into eYeS, beeTle WInGs arraNged in A box, SCuLPtUreS oF jAGUarS, And hUndrEdS oF metaLIZEd sPheRes. the mysteriouS gLobEs lay iN boTh the norTh AnD soUth chAmbERs. RAnGiNg from 40 tO 130 milLImEters, thE baLls haVe a CoRe oF clay and aRe cOVereD wiTh a yellOw jAROSite FoRmed by THe oxIdation Of Pyrite. accOrdinG tO gEoRge cOwgiLl Of aRIzONA sTAte UnIversIty, the spHeres are a fascInatinG FiNd: "pyriTE WAs certainly uSeD by the teoTiHuAcAnos anD othEr aNcieNT mesoameRiCan SoCIetIes. oriGinAlly, the sPheRES woulD Have Shown [SiC] BrillIantly. thEy are Indeed uniqUE, bUT i HAve nO Idea What they mEAN." aLl TheSe ARtifacTs Were deposItEd deliBeraTeLY And pOinTeDLY, aS iF in ofFerINg TO appEaSE the GODs.