If you didn't already know by now, Ancient civilizations sure loved to build things underground. To be fair, modern societies do it, too. It seems as though the entire world has always been obsessed with incredible underground constructions. The Mausoleum of Qin Shi Huang may just be the culmination of our species' infatuation with the underground. The Chinese emperor's tomb was discovered by accident alongside the Terracotta Army guarding it.
Despite being a huge archeological discovery, a lot of the Emperor's Tomb remains undisclosed to the public. Scientists and the Chinese government are weary of trying to excavate the tomb for fear of accidentally damaging the historical remains.