Tello is well-known for his discovery of 429 mummy bundles in 1925 in the Cerro Colorado area of Peru. His findings are the most significant source of information regarding the Paracas culture, which dates to 750 B.C.E-100 C.E. The Tello Obelisk, an eight-foot high obelisk located in Peru at the archaeological site of Chavín de Huantar, is also named after for his discovery of it.