Entering the TombAn entrance to a Maya burial chamber is decorated with vibrant red wall murals—the first look scientists have gotten of a mysterious tomb discovered in 1999.For the first time, a team of researchers from Mexico's National Institute of Anthropology and History (INAH) recently entered the tomb, which also contains 11 vessels as well as pieces of jade, according to an INAH statement.(Related: "Pictures: Blood-Red Pyramid Tomb Revealed by Tiny Camera.")A commonly used color often chosen for royal tomb adornment, red signified blood to the Maya and was considered a sacred life force, said David Stuart, a Maya scholar at the University of Texas, Austin.The tomb is located in southern Mexico in a jungle-shrouded area called Palenque, a powerful Maya political center from A.D. 500 to 700 and now a famous archaeological site.So who is buried within? It's too soon to tell, as no human bones have been studied at this point. But further excavation will likely unravel the mystery of who was laid to rest here and why.(See "Tomb of Maya Queen Found—'Lady Snake Lord' Ruled Centipede Kingdom.")—Catherine Zuckerman

Photograph courtesy INAH