A 34-year-old woman and her 2-year-old son were burnt to death early yesterday morning after a fire broke out in the hotel they were staying at in Vathi Square, a run-down area of central Athens. The remaining residents, many of whom tied sheets to their balcony railings to attract help, were evacuated from the Dodoni Hotel. But the woman and her son had been staying in a room with no window or balcony, police said. According to firemen, the blaze probably started when a gas canister, being used by a resident to make coffee, exploded. Sources said the hotel may have had a fire safety certificate but that the fire-warning system was not operational. Vathi Square is a known hangout for drug addicts. The night watchman at the Dodoni Hotel reportedly died of a drug overdose earlier this year.