Rome's Colosseum has been closed to mourn a worker who fell to his death at Italy's most-visited monument. The 22-year-old worker Andrea Moretti specialized in working at altitude on ropes. He died on Tuesday while installing cabling for an illumination project. Italian Premier Giorgia Meloni expressed shock and sadness. She called his death unacceptable especially in the workplace. Authorities were investigating to determine the circumstances of Moretti's death. Some visitors had already entered the Colosseum on Wednesday morning before the closure.