The Lead Masks Case — Two Men Found Dead on a Brazilian Hilltop (1966)

On August 20, 1966, a young boy flying a kite on Vintem Hill overlooking Niterói, Brazil discovered the bodies of two men — electronic technicians Manoel Pereira da Cruz and Miguel José Viana — lying side by side on the grass, wearing formal suits and crude lead eye masks fashioned from metal sheets. Beside them lay a notebook containing cryptic instructions: 'At 16:30 be at the determined place. At 18:30 swallow capsules, after effect protect metals await mask signal.' An empty water bottle with remnants of an unidentified substance was also found. The two men, both experienced in electronics, had traveled from Campos dos Goytacazes to Niterói on August 17, purchasing the lead masks, a waterproof coat, and a bottle of water before ascending the hill. Autopsies were inconclusive — the bodies had decomposed in the tropical heat before discovery, and the coroner could not determine whether they had been poisoned. No drugs or toxins were identified. The case remains one of Brazil's most famous unsolved mysteries. Theories range from a failed UFO contact attempt (both men were reportedly interested in 'scientific spiritualism') to accidental poisoning during an electronics experiment to murder. The lead masks and the coded note have never been satisfactorily explained.